History Retool / LiveActionTelevision

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[[folder:Doctor Who]]
''Series/DoctorWho'' thrives on this. In chronological order:
* The show was originally pitched as an educational show, and soon retooled to the scifi story it is today. Originally it was supposed to alternate between historical stories set in the past, and scientific ones set in space (which is why the first two companions were a history teacher and a science teacher). This happens as early as the second serial, which features the Daleks (justified as educational by Verity Lambert because of the anti-war moral), and there's some rather half-hearted forced educational moments in later Season 1 serials (such as a scene where Ian and Barbara pause to discuss Roman means of building arches while on the alien planet Marinus), but by Season 2 even that was abandoned in favour of serving up fun adventure stories.
* The personality of the First Doctor got this a couple of times due to EarlyInstallmentWeirdness. He was originally intended to be a TricksterArchetype, the TokenEvilTeammate and constantly getting his friends into trouble, with either Ian or Barbara being TheHero depending on the story. However, it was decided that his character was too unlikeable for children, and the BottleEpisode "The Edge of Destruction" was written quickly to serve as his HeelRealization, after which he became a much more helpful and warm character and quite often TheHero. His final ReTool was hinted at in "The Aztecs" but hit full-force in "The Reign of Terror", and was for him to become a more comical character whose meddling would often get him into weird trouble [[HilarityEnsues with hilarious consequences]]. All of these alterations were carried over to every other Doctor.
* Every single time the Doctor regenerates into a new actor, it comes with changes of the Doctor's personality and show feel. This is almost certainly the only reason ''Doctor Who'' could become the LongRunner that it did. The first regeneration (Hartnell into Troughton) was a relatively small change, but Troughton into Pertwee completely transformed the show's genre, and Pertwee into Tom Baker completely transformed it in a different direction, and again... A basic list, relying on generalisations:
** Hartnell: A grumpy but good-hearted Doctor in an EdutainmentShow dealing mostly with historical adventure stories and fairly thoughtful sci-fi.
** Troughton: A comical, silly and straightforwardly heroic Doctor. Show dropped the historical adventures and began focusing exclusively on aliens. The stereotypical Troughton story is a 'base under siege' where a small community of scientists are trying to do something important while some sort of [[PeopleInRubberSuits rubber suit monster]] and/or foam is taking over. Six-part adventures become more common than the four-parters that were the main format of the Hartnell era, but the serial length is still very irregular.
** Pertwee: A serious, charming aesthete ActionHero Doctor in a TuxedoAndMartini-MonsterOfTheWeek genre mashup show (after all three regulars including the current Doctor decided to leave at the same time). The Doctor has a whole new backstory and has been exiled to Earth. The show takes on a much stronger MonsterOfTheWeek format due to said exile -- Hartnell and Troughton would often have general adventure stories with no clear monster figure and themes of exploration or dealing with the culture of a PlanetOfHats, but Pertwee got to fight a new ridiculous [[AttackOfTheKillerWhatever Killer Whatever]] alien (and/or, later, his EvilCounterpart) every month without fail. Companion role goes from being a small group of mixed-sex travelling companions to a primary young, female partner (Liz, Jo, Sarah Jane) and a larger pool of UNIT coworkers who can be drawn in and out of stories as needed. Serial length standardises as six-parters with a four-parter OnceASeries. And everything's suddenly in colour! The most extreme retool to date, it was so successful that the format hung around for most of Tom Baker's tenure.
** Tom Baker: A slightly [[ByronicHero byronic]] ManChild Doctor with [[ComicalOverreacting funny mannerisms]]. Show drops the secret agent elements but keeps the MonsterOfTheWeek formula, very rarely dealing with recurring enemies (only two Dalek stories in the whole seven-year tenure). Show also begins taking heavy influences from Film/HammerHorror films, giving it a gothic tone and {{Genre Shift}}ing the show into 'horror' rather than sci-fi, though this is dropped in favour of comedy and pure sci-fi later after a MoralGuardian crackdown. The final season shows a sudden increase in production values, the theme music and visuals are changed, the Doctor starts wearing a more costume-y outfit in order to provide more visual identity and the writing gets dark again, though staying out of horror for the most part. Companion role is streamlined, dropping the coworkers for simplicity and not bothering with male companions for CastSpeciation reasons, focusing on a single young, attractive female character.
*** The Fourth Doctor's personality went (inorganically) through three different archetypes depending on who was producing his run, as each writer envisioned a different tone for the show. His first personality, during his GothicHorror-influenced era, was a CreepyCute NightmareFetishist ManChild who occasionally struggled with big moral decisions but was also very unpredictable, possessing BlueAndOrangeMorality. His second personality, during his LighterAndSofter-cum-DenserAndWackier era, was PlayedForLaughs - much more of a {{Cloudcuckoolander}} and also much more of a NiceGuy (dipping into FunPersonified at times), although also more of an AttentionWhore and more awkward to deal with. His third personality, when the show decided to get DarkerAndEdgier again, made him philosophical, [[ByronicHero Byronic]], dignified and quite morbid, developing some {{Chessmaster}} qualities and dispensing with a lot of the childlike aspects of his character. Broadly, his taste in hat colour indicates which personality he's going through at the time - a brown hat for [[CharacterizationTags goth!]]Four, a green hat for funny!Four and a red hat for old!Four.
** Davison: A subtle and human Doctor to contract with the previous LargeHam Doctor, whose sonic screwdriver is destroyed as a symbolic attack on some of the lazier Tom Baker writing. Show adds SoapOpera elements like a large rotating cast of companions and a bigger focus on the Doctor as a vulnerable and emotional figure (where Tom Baker had verged on InvincibleHero) and even going into soap-like scheduling for an ill-advised period. Horror is back on the table and {{Wham Episode}}s and ContinuityPorn are the name of the game (including a whole season of recurring monsters in the run-up to the anniversary special), and a companion gets killed off for the first time since William Hartnell.
** Colin Baker: An attempted CharacterCheck, much DarkerAndEdgier Doctor; arrogant, violent and verbose. Stories attempt {{Deconstruction}}s of standard Doctor stories and begin to incorporate some engagement with the implications of time travel itself (which is usually just used as a device to get the Doctor into wherever the adventure will happen), like FutureMeScaresMe and TimeyWimeyBall. More stylised, crazy sets and costumes occur. The format changes to 45-minute episodes after it gets UnCancelled.
** [=McCoy=]: A particularly impossibly wise Doctor who is sociopathic and manipulative, who also happens to be a cheery, funny vaudevillian. After some EarlyInstallmentWeirdness, starts focusing strongly on the companion's home life and personality, as well as continuing the trend of deconstructing the Doctor's relationship with the companion. The story moves in a more arc-based direction, but the show is cancelled here.
** [=McGann=]: A rather naive and enthusiastic Doctor, aimed at being an AdaptationDistillation of traits from the popular Fourth Doctor. Show begins taking heavy influence from ''Series/TheXFiles'' and is the first to introduce explicit romance between the Doctor and his companion (although Tom Baker and Pertwee had both dabbled in ShipTease). Focus remains on the human companion rather than on the Doctor. (The ExpandedUniverse version of him changes a great deal from this, though.)
** Richard E Grant: Gallifrey has been destroyed and the Doctor has a whole new truckload of {{Angst}} to be a StepfordSmiler about, and the Master gets to become [[HoYay the Doctor's boyfriend]] with a HeelFaceTurn. Pertwee-era-{{Pastiche}} story, and the companion's personal life continues to be important, but the Doctor contains most of the focus. {{Mythology Gag}}s run thick. Also, it's WebAnimation. {{Retcon}}ned out when a new live action series got a go-ahead.
** Eccleston: Gallifrey has been destroyed in the Time War and the Doctor has a whole new truckload of {{Angst}} to feel about it. The focus remains on the human companion, and a whole lot of SoapOpera elements are explicitly added to genre mashup levels. Since production values are notably better the monsters tend to be quite self-consciously {{camp}}y, and the science fiction elements are intentionally very soft. The Doctor is also portrayed as almost always knowing the monsters he's up against, a new development. However, the mythology of the series is deliberately shied away from in order to bring in new fans. Also, we focus on time travel rather than space travel; when we leave Earth it's for an Earth space station in the future or the planet humans migrated to and still call Earth in the further future. That part continues into the Tennant era, changing only with series four. There's a theme of humanity's journey that runs through Nine and Ten's years.
** Tennant: Much more romantic and gentle than Eccleston's Doctor, but also much more brutal and ruthless. Feel of the show remains much the same as with Eccleston due to his extremely short tenure, but takes the focus back onto the Doctor rather than on the companions, and deals with constant themes of morality, loneliness and [[ShootTheDog Shooting The Dog]]. First Doctor whose seasons turn out to constitute a MythArc in the end.
** Smith: Very similar to Tennant's Doctor, but more childish and less moody. With no prior cast members involved and a new showrunner, the mood changes to a "cosmic fairy tale" theme with a much stronger focus on {{Time Paradox}}es than ever before, and incorporating strong elements of SexComedy. Horror episodes are significantly more common during this period, and MythologyGags to the Classic series, purposefully avoided before, become thick on the ground. We also see more alien worlds -- they're still HumanAliens, of course.
** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero marked by his CharacterDevelopment from GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are gone. Series 8 has him take more of a backseat to his companion than he'd done previously in the new series (she being retooled from her debut in Smith's final season), but he returns to the show's center afterward. Horror episodes and grisly content are common as the tone becomes melancholy and mature. The Doctor spends more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]] than he used to. Human companions have lives outside of the TARDIS and the first non-human companion of the revival is introduced. Pacing is notably slower, especially in Series 9, which is mostly multi-part stories. With this Doctor a throwback to those of the Classic Series (especially One, Three, Four, and Six), ContinuityPorn runs rampant. Like the Eccleston and Tennant eras, mostly confined to Earth and human outposts.
* The all-but-abandonment of "pure historicals" (episodes with no science fiction elements other than the Doctor and his TARDIS himself) and their replacement with much rarer "pseudohistoricals" (stories where the Doctor will travel back in time to fight an alien) was an early attempt at this, as historicals were proving much less popular with audiences than the PeopleInRubberSuits. The first story to contain pseudohistorical elements was "The Chase" (which contained a short WackyWaysideTribe sequence involving Daleks on the Mary Celeste), and the first true pseudohistorical was "The Time Meddler" - the reveal that it was another time traveller causing the mayhem was a shocking twist to an audience expecting a CostumeDrama with HornyVikings, [[SeinfeldIsUnfunny but pretty much expected now]]. The last pure historical of this era was "The Highlanders", although the Peter Davison story "Black Orchid" also fits the strict definition of this story type.
* The [[LastOfHisKind wiping-out-from-all-of-existence of the Time Lords]] between the show's 1989 cancellation and its 2005 resurrection might also be considered a retool. Actually, the introduction of the Time Lords counts as a bit of retool in itself. Originally the Doctor simply came from a mysterious alien civilization, with no more details offered.
* The restoration of Gallifrey in the 2013 50th Anniversary Episode is also one of these. It almost immediately preceded the Eleventh Doctor's regeneration episode, and helped end AnArc that had been pushed as long as it could have been and now only served to hold the character back.
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[[folder:A-L]]
* This has been done several times in ''Series/{{Alias}}''. In one episode during a later season, an overarching storyline is resolved, Sydney finally admits her love for Vaughn, and the show's premise fundamentally changes as a result.
* ''Series/{{Angel}}'' was retooled after the first season, which was heavily FilmNoir [[OccultDetective supernatural detective]] style and became much more modern fantasy oriented. The fifth season showed a dramatic change with the main characters becoming the operators of their enemies' law firm at Wolfram and Hart, including near limitless resources.
* ''Series/AntFarm'' took the kids out of the local school (and by extension the A.N.T. program) and moved them into a boarding school owned by a high-tech corporation... for some reason. China's family got cut from the cast as a result.
* ''Series/AreYouAfraidOfTheDark'' attempted this with a "relaunched" series that aired three years after the conclusion of the original series, and had almost none of the production crew or cast (save for Daniel [=DeSanto=] as Tucker, who formed the "New Midnight Society"). The revamped show did well enough to last a further two seasons.
* ''Series/TheATeam'' did this in its final season, via solving the central conflict of the show. The team is captured by the government, and decides to work ''for'' them instead of avoiding them.
* ''Series/TheAvengers'' was originally about Dr. David Keel (played by Ian Hendry) teaming with a mysterious secret agent named John Steed and their investigation into crimes. In the second season Hendry left and Steed became the lead. Steed then gained a new partner, the leather-clad, judo-knowing Cathy Gale, the first ActionGirl of many that Steed would be partnered with through the decade. After her would be the most famous to American audiences, Emma Peel and finally Tara King.
* ''Series/BarneyAndFriends''' format has constantly changed. Season 4 introduced a fully redesigned school set. Season 7 moved the setting from a school to a park. Season 9 mixed park segments with parts on a white background featuring just the dinos. Season 10 introduced Riff and took on a TwoShorts format. Season 12 reverted to the full-length format and focused on story genres. Season 13 was about countries and cultures.
* After its cancellation and renewal, ''Series/{{Battlestar Galactica|1978}}'' was retooled into ''Series/{{Galactica 1980}}'', which proved [[DorkAge so unpopular]] that many fans of the original show [[FanonDisContinuity refuse to acknowledge its existence]] (with the possible exception of the "Return of Starbuck" episode).
* One of the most infamous examples was ''Baywatch Nights''. This ''Series/{{Baywatch}}'' spinoff involved the show's resident police officer, Sgt. Garner Ellerbee (Gregory Alan Williams) decide to open a detective agency, being joined by Mitch Buchannon (Creator/DavidHasselhoff) and Ryan [=McBride=] (Creator/AngieHarmon) and have them deal with street crime. Then when the show proved to be a flop, the producers were inspired by the success of ''Series/TheXFiles'' and decided to replace Ellerbee (who, again, ''founded the agency'') with a paranormal investigator and turn the show into "David Hasselhoff fights aliens, mutants and ghosts".
* The British cop show ''Series/{{Bergerac}}'' had a bizarre final series in which the lead character relocated to France and became a private eye, to little consequence.
* Gritty police drama ''Series/BetweenTheLines'' ended series 2 with a very over-the-top {{Cliffhanger}}, so much so that when it returned for series 3, the only way out was to reshape the show with the lead characters [[spoiler: no longer cops and all working as private detectives]].
* ''Series/TheBill'' has undergone several in its 26+ year lifespan. The most dramatic were in 2002 (when 7 of the regular long standing cast members were killed off in a single episode), and 2009 (when the series moved to HD, started being broadcast after {{Watershed}}, and completely replaced its theme music with a different tune for the first time ever).
* ''Series/{{Blackadder}}'':
** The original pilot for featured the characters being much closer to those in the second series. It was only after the objections of Rowan Atkinson (who felt they hadn't provided him with an actual character) that the characters were changed around.
** The first season had Blackadder as a simpering coward and borderline ButtMonkey, and Baldrick as HypercompetentSidekick - his "cunning plans" actually tended to be cunning. From the second season onward, Blackadder became the DeadpanSnarker that the show is best known for; and Baldrick became a classic BumblingSidekick. The result was a much funnier show.
** The change in scale also affected the character of the show. Unlike the ambitious, near-filmic original, the second series was far more small-scale and almost entirely studio-based. While this was pretty much forced on them due to the budget being reduced, Ben Elton (who replaced Atkinson in the writing partnership) also told Curtis he thought they should have done it in front of a studio audience anyway. In addition, he said "Doing it on film in this glorious sort of vastness was probably a mistake. Rowan falling off a horse at 200 metres is not really any funnier than anyone else falling off a horse at 200 metres- get the camera in close and he’ll make you laugh."
* Bob Newhart's third series ''Bob!'' was the story of Bob [=McKay=], a greeting card artist who had a few decades earlier created a semi-successful comic book character called "Mad Dog". When Ace Comics offers him a chance to revive the book he quits the greeting card company and deals with the wacky people who work for the comic book company. After the first season the series was renewed, but in the first episode of the second season it is explained that Ace Comics went out of business and Bob crawled back to the greeting card company to get his job back there (and deal with the wacky people there). This version only lasted a few episodes before it was canceled.
* ''Series/BoyMeetsWorld'' got retooled several times of the course of its run:
** Season 2: Cory, Topanga, and Shawn start going to John Adams High. Mr. Feeny follows them. Eric has a much larger role, and begins to take on TheDitz traits of his "[[TheDitz modern]] [[ButtMonkey persona]]." Topanga abandons her GranolaGirl roots and becomes a HollywoodNerd. More of Shawn's [[ParentalAbandonment home life]] is revealed. Mr. Turner, "the bullies," and [[LocalHangout Chubbie's]] are introduced. Also, the show loses [[ChuckCunninghamSyndrome Minkus]], and abandons the old theme song and credits sequence.
** Season 5: At the start of their senior year, Shawn reunites with his LongLostSibling Jack, who joins the main cast. Shawn, Jack and Eric (now attending college) move in together in an apartment, and Jack becomes Eric's best friend and comedy sidekick. Heretofore {{Kidanova}} Shawn gets a steady girlfriend Angela, who becomes a recurring character. Mr. Turner falls victim to ChuckCunninghamSyndrome and main high school set is changed to the senior hallway. The show gains an increased focus on running storylines, something it had already been experimenting with. Finally, the classic ThemeTune (with lyrics!) is introduced.[[note]]This retool even got a LampshadeHanging, with Chubbie's getting redesigned into a new restaurant at the start of the season.[[/note]]
** Season 6: Cory, Shawn, Topanga, and Angela graduate and go to [[CaliforniaUniversity Pennbrook University]]. [[RunningGag Mr. Feeny follows them]]. Angela becomes a member of the main cast. Cory and Topanga get engaged, but don't exactly make a mad dash for the altar. Rachel joins the cast and moves in with Eric (now a full-on {{Cloudcuckoolander}}) and Jack, setting up a LoveTriangle. Alan, Amy, and Morgan are reduced to CommutingOnABus.
* ''Series/BuckRogersInTheTwentyFifthCentury'', which aired opposite ''Battlestar Galactica'', was retooled to be more like the latter (and at the time when ''Galactica'' was cancelled, no less). The second season was a departure from Buck and Wilma protecting Earth from evil. In the second season, Buck, Wilma, and Twiki were stationed aboard a research vessel, but their adventures were somewhat similar to the first season, though some of the main characters were replaced by others, like Buck's new sidekick, Hawk.
* ''Series/BuffyTheVampireSlayer'' introduced several new characters and a college setting, leaving most of the background characters from high school behind, after Angel, Cordelia, and Wesley left Sunnydale in the third season finale to create a {{Spinoff}} in ''Series/{{Angel}}''. It was retooled again in the sixth season, emphasizing that Buffy had to take on the role of an adult now and there was no school at all.
* When the spy craze overtook TV in 1965, the detective series ''Series/BurkesLaw'' was turned into ''Amos Burke, Secret Agent''.
* CBS' primetime drama ''Series/CentralParkWest'' suffered this. The show was originally about a pair of siblings who immersed themselves in the world of high-class socialites, and got caught up in all the backroom deals and intrigue that followed. In the second season, the theme song was changed (from a sultry and mysterious jazzy song to the type of theme you'd hear on a cheesy soap opera), the show was marketed as "CPW", half the cast was jettisoned (including one of the two siblings), Raquel Welch was cast as an [[{{Dynasty}} Alexis Carrington-esque]] business owner, and many story arcs were dropped. However, it could be said that the show immediately improved as a result of this retool (especially since the writers dropped the pretenses and started having fun with the material). Then, it was cancelled shortly thereafter.
* ''Series/CharlesInCharge'' was retooled when it moved from network TV to syndication, discarding Charles' original employers and girlfriend and replacing them without changing the house where he worked -- and managing to maintain a single continuity through the process.
* ''Series/{{Charmed}}'' had a change after the third season due to [[McLeaned Shannen Doherty's departure from the show]] and Creator/RoseMcGowan was added to the cast as fourth sister Paige, and the dynamic changed with Piper now being the eldest, Phoebe being the middle child, and Paige acting as the youngest. The opening credits were also changed with Alyssa Milano receiving first billing and Creator/HollyMarieCombs getting the "and [insert name] as [character]". There was another retool for the final season which had the character of Darryl written out; new characters Billie, Christy, Coop, Dex, and Henry introduced; and the temporary departure of Leo mid season until the finale. Also Phoebe started wearing actual clothes.
* Throughout the three series of ''Chef!'', only three actors remained constant, although this was explained in the first episode (Le Chateau Anglais had a high turnover rate), but the third season seemed a real departure from the previous tone, as Gareth's wife left him, a man from OopNorth bought the restaurant off of him, an [[CulturalTranslation American was added to the primary cast]] (although one had previously appeared in the first season), the soundtrack got a bit worse, and the ''entire'' kitchen staff started to develop personalities. Nevertheless, managed to be an example of a successful retool.
* ''Series/{{Coach}}'' had Hayden Fox leave Minnesota State University to coach a pro team in Orlando in Season 8.
* ''The Col'n Carpenter Show'' was a spinoff of ''The Comedy Company'' revolving around Kym Gyngell's signature character, a simple-minded, usually unemployed man approaching middle age. It ran for two seasons and was retooled twice during that time. Carpenter was the only regular character throughout the whole series, so it changed the show's dynamic when he moved in with his mother, then again when he moved into a flat with two roommates.
* ''Series/{{Community}}'':
** Season four had some minor retooling by virtue of original show runner Dan Harmon's departure, but for the most part the format remained the same and at worst the season is simply considered a DorkAge by many fans, a fact which is parodied in the show under the pseudonym 'the gas leak year.' With Harmon's return for the fifth season, a lot of the early episodes in season five involved reversing the changes from the previous season, including giving the study group a reason to get back together, dropping the 'Changnesia' plot for Chang, and giving Pierce's departure proper closure by [[spoiler:[[KilledOffForReal killing him Off For real]]]].
** Lampshaded in the first episode of its fifth season; most of the study group have left Greendale, but have generally been unsuccessful in their new careers or found them unfulfilling, forcing them back to the college for more study. Abed lampshades the fact that bringing the group back together for more shenanigans around Greendale is akin to a retool, explicitly referencing the ninth season of ''Series/{{Scrubs}}''. Not surprisingly - considering the show's penchant for meta and self-awareness - this season sees some of the biggest changes in the format of the show; two of the seven main cast members leave (one of whom is replaced by a surprisingly ''not'' SuspiciouslySimilarSubstitute {{Expy}}), a season one recurring character who had a case of ChuckCunninghamSyndrome returns, and Chang is finally (if reluctantly) accepted as a regular member of the study group.
* ''Cursed'' was a sitcom starring Steven Weber as a man [[ExactlyWhatItSaysOnTheTin cursed]] by his ex-girlfriend and his unending stream of bad luck. This somewhat one-note premise having a limited appeal, it was renamed ''The Weber Show'' and retooled as a kind of gender-reversed ''Series/WillAndGrace'' focused on Weber's friendship with a LipstickLesbian. The show still only lasted one season.
* The first season of ''Series/DarkAngel'', aired before the World Trade Center attacks, was a story about SuperSoldier Max hiding from a MegaCorp and engaging in Robin Hood-esque criminal acts on behalf of Logan, a guy who called out corrupt authority figures on television. Max had to balance this secret life with her normal young adult life, hanging out with her fellow hip young friends in a borderline {{Dystopia}}. The second season, aired less than a year after 9/11, when anything that portrayed America negatively labelled you as an un-American terrorist, dialed back a lot of the CyberPunk aspects. Max didn't have to deal with corrupt cops and powerful criminal gangs in their daily lives nearly as much, and the MegaCorp was gone and replaced with a vague AncientConspiracy. Max didn't steal from evil authority figures on Logan's behalf anymore, instead getting into trouble dealing with other super soldiers. And her friends were almost completely phased out, getting rid of the cool urban feel to the show.
* ''The Doris Day Show'' changed formats almost every of the five seasons it was on air. Originally it was about the eponymous star as a widowed mother of two sons who decided to move back to the family ranch. In season 2, she took a job at a San Francisco magazine and commuted to work. A year later the family moved to an apartment in the city while Day's character went from a secretary to a reporter. For the last two seasons the show was completely overhauled; the two sons and most of the supporting cast (which had changed every year up to that point) were dropped without explanation, Doris became a swinging single career woman a la Mary Tyler Moore and she was referred to as always having been a reporter. The only thing that remained constant about the show during its five-year run was its lead actress.
* The 80s teen sitcom ''Double Trouble,'' starring twins Jean and Liz Sagal (sisters of Katy), revolved around their life in Des Moines, Iowa, being raised by a single dad (Donnelly Rhodes) who ran a dance studio. The second season did a major retool and sent them to New York City, where one sister tried to make it as a dancer and the other attended fashion school with a tactless, snarky professor. They lived in a townhouse with their eccentric aunt and two kooky single guys. (There was no third season.)
* ''Series/EarthFinalConflict'' did more or less the same thing. Twice, at least -- more (at least once an episode in the second season), if you consider violent changes in tone to be tantamount. The biggest change was killing off ''the lead character'' to make way for a new hero.
* ''Series/EerieIndiana'' only had one season, but got a retool two-thirds of the way into it that included the addition of John Astin and Creator/JasonMarsden.
* ''Series/TheElectricCompany1971'' returned in the late 00s as [[Series/TheElectricCompany2009 an updated version]] -- filled with rapping kids with superpowers fighting bad guys, MindControl plots, and other elements that reek of ExecutiveMeddling. Even Joan Ganz Cooney, the creator of ''Series/SesameStreet'', didn't think it was all that good.
* ITV soap ''Series/{{Emmerdale}}'' was renamed from ''Emmerdale Farm'' in 1989, and became DarkerAndEdgier (having previously been a pleasingly twee saga about the day-to-day lives of farmers). In 1993, they [[KillEmAll killed half the cast in a plane crash]], leaving only a handful of original cast members.
* ''Series/TheEvent'' was put on a hiatus in the middle of its first season and retooled due to low ratings. The show stopped using flashbacks to tell the story in an anachronistic style, the villains' motivations were streamlined, and the heroes made more forceful and less indecisive. The show improved in ratings but was not renewed for a third season.
* ''Series/TheFactsOfLife'':
** Half the cast was dropped after the first season (although some of the girls popped up on occasion during the 1980-1981 season), added Jo to contrast with Blair, and most importantly got better writers. (Even the ''theme song'' improved!)
** In addition, there were three major settings throughout the run. At its heart, the main setting always remained at (or near) the campus of Eastland School, but starting in 1983, much of the action shifted to a gourmet bakery called Edna's Edibles. By 1985, with the core group of girls (Blair, Jo, Natalie and Tootie) in their late teens or early 20s, the girls now began managing a novelty store called Over Our Heads; the explanation for that shift was that a kitchen fire (OffScreen) destroyed Edna's Edibles.
** Another re-tool was planned for the 1988-1989 season, with series star Lisa Welchel being one of the few cast members opting to stay for the to-be-retitled series. The action was to shift back to Eastland, now a co-educational school (done so on Blair's action to save the financially starved school from closing; as she was extremely wealthy, only she had the financial resources to pull off such a move). The set-up was aired in a two-part ''Facts'' episode, "The Beginning of the End/Beginning of the Beginning" (highly reminiscent of the original ''Facts'' pilot, "The Girls School," which aired as a ''Series/DiffrentStrokes'' episode back in 1979), but the series never made it to air. Had the series been green-lighted, ''Facts'' (and its new name) would easily have been NBC's longest-running sitcom at that time.
* The ChannelFive soap ''Family Affairs'' had several retools. The first one [[ArtifactTitle got rid of the eponymous family entirely]], and later ones were even more drastic. None of them seemed to help the ratings, though.
* The 2007 ''Series/{{Flash Gordon|2007}}'' remake was retooled during a mid-season hiatus to combat highly negative fan reactions. The MonsterOfTheWeek format was abandoned in favor of an arc-based storyline, Flash's BlackBestFriend was dropped from the cast and much more screen time was spent on Mongo in general. It didn't save the show from being canceled, although many fans thought it got better after the retool.
* The sitcom ''Flying Blind'' went through a major rework halfway through the first and only series, with the male lead leaving his job as an office drone and becoming a Creator/{{Troma}}-esque underground filmmaker instead.
* After the death of Dolph Sweet, ''Series/GimmeABreak'' was given a massive overhaul. The two older daughters were dropped, the rest of the cast moved from the California suburbs to New York City, and Joey was given [[CousinOliver a younger brother]] (played by Joey Lawrence's younger brother, Matthew). And even that was tweaked in the final season, with Samantha, Grandpa Kiniski and the new NYC neighbors leaving, and Nell's mother, Addele, moving in.
* ''Series/H2OJustAddWater'' drops the leader of the main trio in Season 3. Lewis, the main male character, leaves to go study in America.
* For its fourth and final season ''Series/HannahMontana'' [[DemotedToExtra removed Mitchell Musso from the main cast]], moved the Stewart family into a bigger house, had Lilly come to live with them, and replaced the series' most-used outdoor set (a generic beach) with a [[FictionalCounterpart mock-up of Santa Monica Pier]]. Along with these sweeping changes, the show was renamed ''Hannah Montana Forever''.
* ''Series/HeartsAfire'' changed its setting and most of its supporting cast for its second season.
* ''HumanTarget'' got retooled for its second season, with several changes: the cliffhanger of the first season was resolved immediately and then forgotten, the sets got a new, shinier look, and two new female characters were introduced, one of whom was MsFanservice who contributed little, and the other did nothing but [[ArsonMurderAndAdmiration question Chance's methods but grudgingly admit they worked]] ''every single episode'' and provide a forced romance. Also, the music went from BearMcCreary's sweeping orchestrals to generic action music.
* ''Series/ILoveLucy'' had a temporary retool in the fourth season when Ricky gets a starring role in a movie and he and Lucy and the Mertzes go to Hollywood and stay at a hotel. They move back to New York City early the next season. In the sixth season the Ricardos move to Connecticut and are followed by the Mertzes. In the seventh season the show became the ''Series/LucyDesiComedyHour'', an hourlong show with a special guest star each week.
* ''It's About Time'' was a series made by the creator of the then current ''Gilligan's Island'', and featured that show's slapstick approach. The storyline concerned two Astronauts whose space capsule goes backwards in time and lands in a time of cavemen. Storylines dealt with the astronauts bringing civilization to the local cavepeople, while at the same time trying to fix their spaceship. At the midpoint of the show's first (and only) season the astronauts manage to fix their ship and leave the stone age, only to find that two of the cave people who helped them stowed away on the ship, flipping the storylines to episodes involving the astronauts hiding the cave people from the government while helping them adapt to 20th Century life. [[http://www.youtube.com/watch?v=wqzHLZuXRCo The catchy series theme which explained the premise]] was cleverly flipped and adapted to [[http://www.youtube.com/watch?v=07pPtYb0z80 this for the second half of the season]].
* ''Series/{{JAG}}'': The first and, to a lesser extent, the second seasons on NBC focused primarily on action packed pre-trial field investigations, while the third and later CBS seasons joined that formula together with an equal amount of courtroom and office drama in the stylistic vein of ''Series/LALaw''.
* ''Series/TheJeffFoxworthyShow'' explored this in a series of commercials between seasons (and a ChannelHop from ABC to NBC). Jeff and his TV son are discussing where they have been recently and why everything is so strange. Jeff calmly explains that their new network is retooling their show so it will be even better and his son shouldn't worry. When the boy asks where his Mom is, Jeff tells him that she is being recast.
* 90s NBC sitcom ''Jesse'' (starring Christina Applegate) was, quite typical for its era, about a single woman in her twenties with a major WillTheyOrWontThey plot, but distinguished itself somewhat by originally featuring the main character's family (wacky brothers and gruff father) in major roles, as all of them worked at the dad's bar together. However, that family [[ChuckCunninghamSyndrome vanished]] in the second season as Jesse got a new job at a hospital with young and attractive colleagues, while her girlfriends got more screentime than in the first season. The producers were obviously trying to make the show more similar to [[Series/{{Friends}} a certain other show of theirs]].
* The Japanese ''Franchise/KamenRider'' franchise has gone through several retools:
** The very first season had its lead actor, Hiroshi Fujioka, involved in an accident, which made it impossible for him to continue involved in the show's production for an extended period. Initially, that led to a ''FakeShemp'' Hongo, who mostly appeared as Kamen Rider, played by a replacement suit actor and voice actor, and also through ''StockFootage'' spliced with new scenes. In spite of that, the focus shifted to the supporting cast, and FBI agent Kazuya Taki was introduced as a non-super powered heroic lead. After a few episodes, a new protagonist and Kamen Rider, Hayato Ichimonji, was added, Hongo Takeshi left to fight against Shocker in other countries, and the show went through several changes, like lessening the horror elements of the first few episodes and the creation of the instant transformation sequence with a "henshin" call that would go on to become one of the franchise's trademarks. Ruriko, Hongo's love interest, was phased out of the series, the hangout spot of the supporting cast was changed and three new girls were introduced alongside Hayato. The soldiers working for the organization Shocker also started sporting a more uniform look with wrestling masks, rather than the varied situation appropriated look from the first 13 episodes. The changes were a success and the series exploded in popularity. Eventually, Hiroshi Fujioka recovered and returned to the series as Hongo, recovering the main character spot after a few months of guest appearances, but, even when he returned, the style of the series didn't shift to its initial one.
** The second series titled Kamen Rider, although more commonly known as ''Series/KamenRiderSkyrider'', also went through a retool. Initially intended to be a reboot of the franchise with a new Rider with theme and origin very similar to the original, also facing an organization very similar to the one of the original series, the show didn't meet expectations regarding its ratings, with the lead character, Hiroshi Tsukuba, being considered uncharismatic and the villains bland. Several measures were taken to solve those issues, like getting rid of the original villain, while introducing a completely new enemy commander not based on anyone from the original series, phasing out a comic relief character unconnected to the main plot, and adding humorous moments with the interaction between the villains themselves at times, and, finally, bringing back the original 7 Kamen Riders, dropping the reboot aspect from the series. Their return was a success, boosting the show's ratings, leading to many appearances throughout the series. Although most Kamen Rider series up to Black RX had appearances from older Kamen Riders, Skyrider's had the biggest amount of them, and also the most significant ones. Initially, their appearance was so rushed, that many were just ''FakeShemp''s, appearing transformed all the time, voiced by replacement voice actors. After a few months though, all of their actors besides Kamen Rider 1's and Amazon's actually returned to the series.
** ''Series/KamenRiderHibiki'' experienced a massive retool about 30 episodes into the 48 episode series. The show, not initially intended to be a ''Franchise/KamenRider'' season to begin with, was very different in terms of what it was doing, and took a while to grow on people. Due to the original's staff refusal to take several cost saving measures, the retool was both an attempt by [[ExecutiveMeddling executives]] to bring the show more in line with what a "normal" Kamen Rider was supposed to be and also reduce the show's costs. The retool, although successfully increasing the show's ratings and costs, was criticized by fans, critics, and even the cast itself, who pretty much ''hated'' the changes, and the executives that had ordered it all got lambasted for their gross mishandling of one of Toei's premier franchises.
* ''Series/KirbyBuckets'', during its first two seasons, was a sitcom about a teenage boy who wanted to be a professional cartoonist, not unlike ''Series/OutOfJimmysHead''. The format then shifted in season 3 to become a dimension-warping action show. The cartoon cutaways were dropped, and the episodic format was replaced by a serial-style series.
* The ''Series/KnightRider'' (2008) remake received a massive retool, dropping the government organization aspect and losing 3 cast members (in the space of two episodes) in a horribly anti-climactic KARR plot 12 episodes into the first season. This arguably improved the show quite a bit and focused on more personal stories, more closely resembling the original show in structure. Then it wasn't renewed.
* ''Series/LabRats'' started off being a show about a teenage boy introducing his stepdad's bionic children into the real world, while occasionally having to fight of dangerous threats. The last three episodes of Season 3 and all of Season 4 moved the setting to an ''ComicBook/XMen''-style bionic academy in the middle of the ocean and focused more on the Lab Rats mentoring the abandoned bionic soldiers of the previous season's BigBad and the normal teenager starting to become a fighter of his own.
* When ''Series/LaverneAndShirley'' moved from Milwaukee to Los Angeles. They took Laverne's dad, Lenny, Squiggy, and Carmine with them.
* Similarly to the ''Series/HannahMontana'' example above, the fourth and final season of ''Series/LivAndMaddie'' moves the Rooneys to their Aunt Dena's house in Malibu, California following the destruction of their Wisconsin home at the end of season three, adds Liv and Maddie's [[CousinOliver cousin Ruby]] to the cast, and portrays the twins as attending a prestigious college. Also, the season is renamed ''Liv & Maddie: Cali Style''.
* ''Series/TheLoop'' was originally conceived as more of a RoommateCom being about a young executive balancing his hard-partying lifestyle, crush on his roommate, and his housemates' hijinx with his serious job. Beginning with the second season, two of his housemates [[ChuckCunninghamSyndrome disappeared without a word]], and the series became a more traditional WorkCom, focusing on the wacky hijinx at his job.
* Struggling soap ''Series/{{Loving}}'' moved from its suburban setting to New York City and became ''Series/TheCity''. The retooled version wasn't any more successful than the original, and the show was soon cancelled.
[[/folder]]

[[folder:M-Z]]
* The first three seasons of ''Series/{{MASH}}'' were primarily a wacky comedy, focusing on "antics at the front". With the departure of main characters Trapper John and Henry Blake, and the arrival of much more serious replacements [=BJ=] Hunnicut and Sherman Potter, the show transformed into a {{Dramedy}} series. It also lost its LaughTrack along the way. Most episodes dealt with serious issues such as racism, homophobia, sexism, and of course, the horrors of war.
* After the first season of ''Series/MajorDad'', the setting was moved to a different military base, with some changes in the cast.
* ''MamasFamily'', like ''Charles in Charge'', got retooled when it moved to syndication and replaced the entire family with the exception of Vicki Lawrence as Mama.
* In the first season of ''Series/{{Mannix}}'' (1967-68), the title character worked for a detective agency called INTERTECT that utilized state-of-the-art (for its time) computer equipment to solve crimes. However, Mannix generally disregarded the computers and the agency's rules to solve crimes his own way. Creator/LucilleBall (''Mannix'' was the last show produced by Creator/DesiluStudios) decided that the computers were over most viewers' heads and asked to have them worked out of the show. This turned Mannix into a more conventional detective series. The [[UsefulNotes/{{Fonts}} font]] used in the credits were based on IBM's corporate font of the time. That font and the theme music were about the only things that transitioned over into the new version of the series. This is best shown in the title cards; in season one, the ''Mannix'' [[http://www.youtube.com/watch?v=CF_49tWPNWA&NR=1 title card is literally a computer card.]] From season two and beyond (1968-75), [[http://www.youtube.com/watch?v=vyZL_3bxD68&feature=related with the better known title card with the shifting letters.]]
* ''Martial Law'' had a rather bizarre case of this. The first-season finale saw Sammo and BigBad Lee Hei falling out of a helicopter over the ocean. Sometime during the summer, though, it was decided to retool the show, and instead of season 2 picking up off where the first had ended, it opened with a regular episode, [[CliffhangerCopout with only scant references to the previous cliffhanger]]. [[note]](Sammo asking if someone who's trying to kill him with a bomb is seeking vengeance for Lee Hei's death, and a fellow officer asking Sammo, "Hey, you fell out of a helicopter into the Pacific and survived... how much worse could a bomb be?")[[/note]] Fans were not pleased.
* Creator/MaryTylerMoore's follow-up to [[Series/TheMaryTylerMooreShow her iconic sitcom]] came in the form of a variety show entitled ''Mary''. Featuring early appearances by Creator/MichaelKeaton, Swoosie Kurtz, and Creator/DavidLetterman, ''Mary'' premiered in the Fall of 1978 and was pulled from the air after three episodes. In midseason, ''Mary'' became ''The Mary Tyler Moore Hour'' and morphed into a sitcom/variety show hybrid about the making of a fictional variety show, and Keaton was the only cast member who remained. The show still wasn't successful and was subsequently not renewed for a second season.
* ''Series/McHalesNavy'' moved to the Italian theater of [=WW2=] in its final season.
* ''Series/MelrosePlace'' started out as a rather low-key drama focusing on a group of twentysomethings living in an apartment complex in California. After the show was critically trashed, the producers hastily fixed the problems and changed up the series. They jettisoned two of the residents (Vanessa A. Williams and Amy Locane), played up newly-hired cast member Marcia Cross's duplicitous character Kimberly, Michael Mancini (played by Thomas Calabro) turned into a villain, and Heather Locklear and Laura Leighton became series regulars.
* ''Series/TheMentalist'': In the middle of season six, Jane finally succeeds in [[spoiler:killing Red John]], and the CBI is disbanded [[spoiler:after it turns out its director Gale Bertram is a member of Red John's organization]]. After a two-year TimeSkip, Rigsby and van Pelt are married and have left the series to run a cybersecurity business, and Jane, Lisbon, and Cho go to work for the FBI out of a Texas office.
* ''Series/TheMindyProject'' took a while to find its footing. Several characters that were present in the first few episodes were written out or suffered ChuckCunninghamSyndrome. The show also changed to become more of a traditional WorkCom. This led to RevolvingDoorCasting, with only 4 characters surviving the first 3 seasons.
* ''Series/{{Millennium}}'' was retooled twice, with the result that the eponymous Millennium Group is completely different in each of the three seasons; an unassuming law enforcement consultant group in the first season, an enigmatic but good-intentioned AncientConspiracy in the second season, and an unambiguously evil AncientConspiracy in the third.
* ''Series/TheMuppets'' is having a minor retool after the first ten episodes of the first season. The reason was due to complaints from many viewers who said that the characters and the tone of the show was too cynical and too much about sex.

* After "Series/MysteryScienceTheater3000'' moved to the [[Creator/{{Syfy}} Sci-Fi Channel]] with their eighth season (and actor Trace Beaulieu, who played Dr. Forrester and Crow) left, they got new villains, a new setting, and (due to ExecutiveMeddling) an actual ongoing plot. At the end of the season, some of these changes were backed off on, with a move to a setting similar to the first seven seasons and a lack of stories that carried on between episodes (though the 10th season had a subplot that was dropped halfway through).
** Sci-Fi also demanded that the majority of the movies featured on the show be strictly science fiction or horror to fit in with the network's other programming.
* ''Series/TheNakedTruth'', a '90s sitcom starring Tea Leoni as a newspaper photographer, was drastically retooled and almost entirely recast each season. In season 1 Nora (Leoni) works at a sleazy celebrity tabloid and had Tim Curry and Amy Ryan for co-stars. Season 2 de-tabloided the paper she worked for and de-zanified the format; only Nora and Camilla (Holland Taylor) remained of the original cast. Mary Tyler Moore and George Segal were added as Leoni's parents. Season 3 saw Nora and Camilla jump ship to another paper with a staff that included Chris Elliot.
* ''Series/NaturallySadie'' was re tooled after the first season with changes including Arden replacing Chelsea as the AlphaBitch, bringing in a new romantic interest for Sadie, and even changing Sadie's character.
* ''Series/{{Newhart}}'' underwent a major change when Kirk and Leslie were written out and Michael and Stephanie were written in. This corresponded with the show becoming more surreal.
* ''Series/{{Nikita}}'' flips it status quo around in season 3 as a result of the events of the second-season finale. [[spoiler:In light of [[BigBad Percy's]] death, Division is taken over by the government and Team Nikita, who start using its resources to hunt down the remaining Division agents who don't join in the HeelFaceTurn]].
* After its first season, ''Theatre/TheOddCouple'' switched to a three-camera format, with a new set and a live audience. Most characters left over from the movies (the Pigeon sisters, Oscar's poker buddies) were jettisoned, with the exception of Murray.
* ''Series/OnceUponATime'': In the jump from the first season to the second, the focus of the plots changed greatly. It went from a 50/50 split between flashbacks and characters working to break the dark curse to a revised format that split the flashbacks with plots that boiled down to "Let's fight various story book characters while redeeming the evil queen and Rumplestiltskin."
* The ''Series/OnlyFoolsAndHorses'' 1988 Christmas special, "Dates". Prior to that episode, the series had focused almost exclusively on Del's get rich quick schemes (it's the original premise; "only fools and horses work!" is a line in the theme song), but in subsequent episodes the series would start to involve Del and Rodney's personal lives much more, aided by the episodes being doubled in length.
* ''Series/OurMissBrooks'': In the fourth season of the TV series, Madison High was razed to make room for a freeway, Miss Brooks and Mr. Conklin went to work for a private school, and Walter and Harriet disappeared from the show along with Mr. Boynton (although the latter would [[TheBusCameBack eventually return]]).
** CanonDiscontinuity was the result. The radio program continued at Madison High as per usual. TheMovie also ignored the fourth season of the TV series.
** A FanFiction story, [[https://www.fanfiction.net/s/10203524/1/Our-Miss-Brooks-The-Reunion-Assembly "The Reunion"]] explains away the last television season as having been AllJustADream of Miss Brooks'.
* ''Series/PerfectStrangers''. After the first six seasons having focused on Larry and Balki living together as roommates in a small urban apartment, the series took a different turn when Larry married his longtime girlfriend Jennifer and bought a large Victorian-style house together. Balki and his girlfriend, Mary Ann, would move in as roommates at the new house and eventually marry as well, and both couples would have children. Characters that had been prominent in the first six seasons (such as Sam Gorpley) were phased out, and the newsroom setting took a significant backseat to the characters' domestic life.
** There was a retool earlier than that with the first season, Larry was an aspiring photographer and both he and Balki worked at a discount store run by the grumpy Mr. Twinkacetti. They also had a platonic female friend named Susan. In season 3 Twinkacetti and Susan were gone and Larry and Balki were now working at the Chicago Tribune where Larry was now a junior reporter and Balki works in the mailroom.
* Although ''Franchise/PowerRangers'' gets a retool every year with new costumes and mecha (and as of the seventh season onward a new cast and storyline), some are more notable than others:
** Midway through ''Series/PowerRangersTurbo'' 4/5 of the main cast were jettisoned in favor of a new cast. This was done to save the show from failing ratings, and the Retool was just enough of a ratings boost to warrant another season...
** ... Which was ''Series/PowerRangersInSpace''. The "kids in high school battle the MonsterOfTheWeek and go home" concept was left behind, and arc-based series with the Rangers, well, [[AC:[[RecycledInSpace IN SPACE!]]]] took prominence. Additionally, the villains of all past series formed a LegionOfDoom. By the time it was over, fans underwhelmed by Turbo and ''then'' hit with the loss of their favorite characters (in addition to the belief that this would be the final series) had forgiven the SeasonalRot and wanted more. [[LongRunners They're still getting it]].
** ''Series/PowerRangersRPM'' was also supposed to be the last season. It was also a vast departure from the way ''Power Rangers'' as usual is done. A post-apocalyptic world's last survivors are in a domed city defended by [[ThreePlusTwo three, then five]], [[SixthRanger then seven]] heroes led by the genius inventor who [[spoiler: actually created the evil AI that started the RobotWar]].
* ''Series/RedDwarf'' has arguably done this four times in eight seasons: the addition of Kryten and the female Holly in season 3, as well as changes in production staff who made the budget stretch much further; the loss of the eponymous spaceship in season 6, leading to much of the action taking place in a single cockpit; the switch to film-like visuals and a more comedy-drama feel in season 7, plus the departure of co-writer Rob Grant; and the almost complete reboot in season 8, when the whole spaceship and crew were recreated as they had been 3 million years previously.
* ''Series/RetroGameMaster'': The first season was primarily a documentary show in which Arino interviewed people from the game industry involved with certain companies or specific franchises. From Season 2 and onward, the "Arino's Challenge" segments that were originally meant to be a secondary portion of the show became the main feature instead.
* Famed sitcom ''Series/{{Rhoda}}'' was retooled at least twice during it's four year run. First, Rhoda and her husband Joe separated and she got a new job. Then, she and Joe got divorced and [[ChuckCunninghamSyndrome he disappeared from the show]], then she got yet another new job, and her parents separated as well.
* ''Series/RobinHood'' was retooled after the WhamEpisode at the end of Season Two in which Marian [[spoiler:is stabbed to death by Guy of Gisborne]] and Will Scarlett and Djaq (the Saracen) are written out of the show. Along with a new writing team and new costumes for the cast, five new characters were introduced to the show ([[CanonForeigner three of whom were not even part of the Robin Hood legend]]) and the premise goes from robbing the rich/feeding the poor to a fight for power over the position of Sheriff, as well as Robin's tangled love-life with two new love interests. The three original remaining outlaws become bit-parts, and all of the storylines of the past two seasons become [[AbortedArc Aborted Arcs]]. In fact, one could go so far to say that if it were not for the character names and the locations, there is little in Season Three that connects it to the legend of Robin Hood at all.
* The 5th season of ''Series/SabrinaTheTeenageWitch'' moved Sabrina to college, introduced several new characters and dropped others. The 7th season dropped the college setting and again dropped and added significant characters.
* ''Series/SavedByTheBell'':
** The show was originally titled ''Good Morning, Miss Bliss'', and was retooled after a brief cancellation. The school moved from Indiana to California, the name of the series changed, several cast members (including the titular Miss Bliss, played by Creator/HayleyMills) disappeared and the focus shifted to the students exclusively.
** The show was retooled again after the gang graduated and moved on to CaliforniaUniversity. In addition to the new setting and a few new characters, the stories became somewhat more "grown-up." The new show didn't make it to a second season.
** ''The New Class'' spin-off was retooled every season with cast changes left and right. The show also featured a different set of non-Bayside episodes every season that took place at different locations including a country club, a mountain lodge, a cruise ship, and the local mall.
* In the 9th season of ''Series/{{Scrubs}}'', the series moves from Sacred Heart Hospital to a medical school and the focus characters become the new students.
* The computer tech show ''The Screen Savers'' that ran on Tech TV then G4 after the merger was retooled as ''Series/AttackOfTheShow''; a more geek and nerd entertainment focused show keeping the same hosts -- at the time, Sarah Lane Kevin Rose and Creator/KevinPereira as well as Brendan Moran. The user created challenge from the last ''TheScreenSavers'' episode was carried over to the first ''AttackoftheShow'' where the winners were revealed.
* ''Series/SecondChance'', an early Fox network offering, was about a man stuck between Heaven and Hell, who got the chance to visit his younger self (played by a pre-''Series/{{Friends}}'' Matthew Perry) to alter the course of his life. The series failed miserably, but the network attempted to build on Perry's charm by retooling the series as ''BoysWillBeBoys'', dropping the afterlife angle and instead focusing on Perry's character and his best friend. The retooled version didn't fare much better.
* ''Shining Time Station'' was retooled twice at the end of its life. First, while keeping its title, the show became a prime time series that aired in spurts as a series of specials. Unlike the child-pleasing daytime series, this version added elements of teen drama (such as the addition of a juvenile delinquent from an abusive household), and featured extensive location shooting, breaking free of the prior version's omnipresent train station interior. (The new-found sense of maturity was actually referenced on the show, as Mr. Conductor appeared as usual to relate an Island of Sodor story to the kids, only to be told that they had outgrown Thomas stories). After a handful of these episodes, the show returned to daytime under the new title of ''Mr. Conductor's Thomas Tales,'' which scrapped the entire cast except for George Carlin as Mr. Conductor, and focused almost entirely on Sodor segments.
* ''Series/SleepyHollow'': During season 2 the pretty serialized main StoryArc left the way for a more broadcast network typical MonsterOfTheWeek approach, which Creator/{{Fox}} signaled in press tours was [[ExecutiveMeddling something they suggested to the show's writers]], and was here to stay. Come season 3, the show acquired a new showrunner.
* ''Series/{{Smallville}}'': Not surprisingly for such a LongRunner, Smallville underwent a 2-3 different retools over the course of its history.
** Season 4 featured the mutant-of-the-week type stories from Season 1-3 falling away in favor of a season-long arc that centered around the hunt for advanced tech from Krypton by various factions, and featured the introduction of ComicBook/LoisLane and the first hints that ComicBook/LexLuthor was starting to grow darker. On the DVD commentary, creators Al Gough and Miles Miller describe the Season 4 premiere as being "like a new Pilot episode" due to the retool.
** In Season 8, the feel of the show got shaken up again; showrunners Gough and Miller left, along with ''four'' major cast members. These departures, combined with a general worry that the show had started to stagnate, necessitated a shakeup. Tess Mercer was introduced and quickly became a fan-favorite character, more DC Comics-related stories and guest stars began to come in, and Clark finally began working at the Daily Planet and exploring the possibility of a relationship with ComicBook/LoisLane. The more mature and {{Superman}}ly tone of the last three seasons had many fans noting that these last three seasons could have quite reasonably been renamed "Metropolis" (a fact that was [[{{LampshadeHanging}} lampshaded]] by lead actor Tom Welling in interviews). The new, Supermanly tone introduced in Season 8 garnered enough praise that it successfully breathed life back into the show and allowed it to last until the end of Season 10, at which point the show was able to properly wrap things up and end on its own terms rather than the network's.
* ''Series/{{Smash}}'' was retooled in its second season, after negative reviews from critics for much of the first season, as well as a very TroubledProduction. The less popular characters were written out and the characters move on to a different musical. [[FridayNightDeathSlot It didn't work out very well]]. The show was cancelled at the end of its 2nd season.
* In a very strange example, Goodson-Todman's 1967-69 GameShow ''Snap Judgment'' was changed for its last three months from a contrived word-association game to a direct clone of ''Series/{{Password}}''.
* ''Series/SonnyWithAChance'' is about small town girl Sonny who joins the cast of her favorite sketch comedy show ''[[ShowWithinAShow So Random!]]''. DemiLovato (who played the titular character) ended up quitting the show and taking a temporary break from acting after season two, to deal with some personal problems and also focus on her music career. Disney retooled it by {{defictionaliz|ation}}ing ''Series/SoRandom''. Yep, the show within the show became the actual show!
* ''{{Space1999}}'' : Season 1 was rather thoughtful and existential with an atmosphere of both genuine danger and epic grandeur and could almost have been shot in black and white. It featured a huge, multi-level main set, awesome space battles, and a sweeping orchestral score. Season 2 was far more simplistic, fast-moving and colourful, with loads more monsters, comedy robots and running around. Several main characters were ditched without explanation, a shape-shifting alien hottie was introduced, there was more focus on the characters personal relationships, the sets were smaller and more intimate and the score was largely replaced by funky guitar. Even the heroes uniforms were changed, with jackets, mission patches and ID badges added for extra colour and interest.
* For its ninth season, ''Series/StargateSG1'' received new characters, arcs, and villains. The production team actually considered retitling the show ''Stargate Command'' and treating the season eight finale "Moebius" as the series finale of ''SG-1''.
* ''Franchise/StarTrek'' has done this on several occasions:
** ''Series/StarTrekTheOriginalSeries'' was retooled to be more action-adventure-oriented after the original pilot, "The Cage", was thought too cerebral by network executives. Most of the crew was recast as well, with Creator/LeonardNimoy and Majel Barrett being the only actors from "The Cage" to make it on to the actual show. And that's with Barrett playing a different character on the show than in "The Cage".
** ''Series/StarTrekTheNextGeneration'':
*** In the transition between its first and second season (see GrowingTheBeard). The supporting characters started to find their niches, the bridge set was slightly redesigned, characters including Worf and Laforge were promoted, and Diana Muldaur came on as the new doctor, Pulaski.
*** The third season dropped Pulaski and brought back Dr. Crusher, but it was also defined by the new uniforms that were more comfortable for the actors (being two pieces instead of jump suits) and had a more professional look to them having high collars, instead of the goofy looking space pajamas of prior seasons.
** ''Series/StarTrekDeepSpaceNine'' brought in Worf in the fourth season and redirected the story towards a new Klingon conflict. While it was due to ExecutiveMeddling, it was considered a successful integration and helped further their Dominion StoryArc by revealing the Klingons were being manipulated by them.
** ''Series/StarTrekVoyager'' underwent a retool in its third season because of the long-running Kazon plotline. The Season 3 premiere, "Basics Part II" effectively ended their storyline because Paramount executives complained that it wasn't exciting enough (which the fans agreed with), noting that the Kazon were akin to the Ferengi in the "[[InformedAbility Dangerous Adversary]]" department. In Season 4, the show was retooled again by swapping out Jennifer Lien for Jeri Ryan, and introducing Species 8472 and the Hirogen as new threats.
** ''Series/StarTrekEnterprise'' was retooled twice in response to bottomed-out ratings, and consecutively no less. The first retool occurred in Season 3 and abandoned the Plot of the Week for a season-long "epic" story arc. When that failed, the show was retooled for Season 4 by bringing in new creative staff and focusing the season on two or three-episode long mini-arcs. Although the quality of the show improved significantly (Season 4 is usually considered the best of the show), it was too little too late and said season proved to be its last.
* ''Series/SuddenlySusan'' was a comedy about a career-minded woman who works as a writer with a local newspaper. During the jump from the third to fourth seasons, several characters disappeared (including Susan's boss, who she had previously admitted being in love with, and a newspaper employee [which was caused by the actor who played him killing himself]), the introduction of a new boss and an overhauled office setting. This retool wasn't really motivated by ratings either, as they had stayed relatively consistent. However, the show was cancelled soon afterwards.
* While billed as a SpinOff of ''Series/TheSuiteLifeOfZackAndCody'', ''The Suite Life On Deck'' featured four of the main characters from its parent series (including the two leads), and simply changed the location from the hotel to a cruise ship.
* After two seasons, the live-action ''Superboy'' series changed its title to ''Series/TheAdventuresOfSuperboy'', and moved the two central characters, Clark Kent/Superboy and Lana Lang, away from college to an internship at The Bureau for Extra-Normal Matters, an X-Files like agency that investigates paranormal phenomena. Along with the title and setting change, the show's stories became darker in tone, and the look of the show became darker as well. Many stories took place at night after the change, and the lighting for the final two seasons was done in a film noir style.
* ''Franchise/SuperSentai'':
** The second series, ''Series/JAKQDengekitai'', was initially going to stand out from [[Series/HimitsuSentaiGoranger its predecessor]] by being DarkerAndEdgier. However, it ended up being so dark that children started to avoid watching the show, so it got retooled. The retool introduced Soukichi Banba/Big One, who, while initially looked upon as a ''ReplacementScrappy'' for Joker, the previous ''BigGood'', ended up becoming one of the most iconic ''Sentai'' heroes to date and one of three candidates for being the ultimate Big Good of the franchise. In spite of that though, the series still hold the dubious honor of being the only Super Sentai series that was canceled, unable to finish a full one year run.
** ''Series/ChourikiSentaiOhranger'' had to have a retool partway through following a terrorist attack on Japan's subway, which was considered too close to the military theme of the season. The show suffered for it and was considered as almost killing the franchise. The show stabilized with the series ''Series/GekisouSentaiCarranger'', but it was only with ''Series/DenjiSentaiMegaranger'' finding a new timeslot for the franchise that it managed to soar again, recover and even surpass the numbers of the years before Ohranger.
** ''Series/TokumeiSentaiGobusters'' went through a retool too. Before its debut, it was touted as the "New Era of Super Sentai", but it quickly became the lowest rated Sentai show in the series' 36 year run (at the time). The initial plotline of the show, regarding the protagonists attempt to rescue their family, and protect the energy source Enetron came to an abrupt end with a climatic battle, alongside with the rushed addition of a new opening theme, gotten from a CD that was already out at the time. It also had a ''crossover'' with ''Film/SpaceSheriffGavanTheMovie'', disregarding how the show had established that it took place in an world with an alternate calendar, differently from Gavan itself, which used the real world one. Finally, afterwards, the popular ''DragonInChief'' of the series, Enter, had a sudden personality change and took the spot of actual ''BigBad'' of the series, with the former ''BigBad'' reduced to ''TheDragon''.
* The first season of ''Series/ThreeTwoOneContact'' involved a team of college students in a room known as the "workshop". In seasons 2-4, it was changed to a cast of middle school-aged kids in a basement. The last three seasons switched to a location-themed format, focusing more on individual hosts (mainly David Quinn) rather than a team. The theme song was also [[RearrangeTheSong remixed]] in the second and sixth seasons.
* Creator/{{ABC}}'s ''Series/TooCloseForComfort'' starred Ted Knight as a newspaper cartoonist who lived and worked in UsefulNotes/SanFrancisco with his wife and two grown daughters. When the show moved to first-run syndication in its final season, it was retitled ''The Ted Knight Show'', Knight's character moved to suburban Marin County and changed his job to co-owner and editor of a newspaper, and his daughters [[ChuckCunninghamSyndrome vanished without a trace]]... although Jim J. Bullock's BreakoutCharacter Monroe, originally the boyfriend of one of the daughters, was retained after the retool.
* ''Series/TopGear'' originally ran from 1977 until 2001, when it was cancelled. Although it relaunched just a year later in 2002, "new" Top Gear is fundamentally different in spirit and character to its predecessor. The original was an informative/factual news and review magazine about cars, and though it became far less dry and more entertaining in the way it did this as time went on, at heart it remained true to that. While the relaunched format isn't uninformative (and does overlap the original in places), it's clear that its ultimate focus is to entertain the viewer, with everything in the end serving that purpose. Unlike the original, it's far more studio based, and more focused on the characters and interplay of the presenters- often intentionally played-up- with the cars often being a means to that end, rather than the point in themselves. Much of the show essentially lets the viewer participate (by proxy) in what James May himself called "self-indulgent cocking-about".
* ''Series/{{Torchwood}}'':
** The third series, ''Series/TorchwoodChildrenOfEarth'', became a politically charged miniseries as opposed to the episodic structure of before.
** [[Series/TorchwoodMiracleDay The fourth series]] moves the primary setting to America, and turns Torchwood into more of a resistance movement as opposed to a short-staffed special ops group.
* ''Series/TheTorkelsons'' was retooled into ''Almost Home'' after the first season, having the mother move to Seattle as a nanny, and jettisoning two of her kids for the kids she was nannying (one of whom was played by a young Creator/BrittanyMurphy.) The tone changed drastically from more [[PlayedForDrama dramatic]] to more [[PlayedForLaughs comedic]]; the setting changed drastically (from a small, quaint Oklahoma village to big city Seattle), and the basic premise changed from "single mother-of-five who's financially struggling, and her dreamy, slightly {{Cloudcuckoolander}}ish daughter" to "strict, poor, small village parent's values clash with loosely-parenting, rich, big city parent".
* ''[[Series/TwentyFour 24]]'':
** Quite a few elements changed between the pilot and second episode (largely to fix elements that didn't work). CTU's director, Richard Walsh, ended up dying anticlimactically one episode after he seemed poised to take on a big role. CTU's interior changed, Tony Almeida lost his heavy Hispanic accent and a number of visual elements (like showing different parts of the environment to symbolize that time is passing) were removed.
** There was a soft retool in season 4. Jack Bauer is fired from his role as CTU Director of Operations between seasons, and gets a new job (albeit one that still gets him involved in the main action) and girlfriend. Additionally, most of the main characters from previous seasons have inexplicably disappeared in favour of a new boss, VoiceWithAnInternetConnection, etc. However, the writers lost their nerve -- by the season's midpoint, Jack was working for CTU again and most of the old cast had returned anyway.
** Season 7 is where they did the [=retool=] ''right''. The action is moved to the opposite side of the country, Jack is neither a federal agent or a federal fugitive, he's teamed up with a DistaffCounterpart, [[GovernmentAgencyOfFiction CTU]] has been disbanded (its role is mostly filled by the FBI), and the few returning characters either having gone underground or [[spoiler:[[FaceHeelTurn Face Heel Turned]]]].
* ''Series/{{Unforgettable}}'' was canceled after its first season, then UnCanceled a year later because a couple cable channels were eyeballing it. As a result season two has completely new sets, swapped out most of the supporting cast (though they kept the coroner), and the season premiere ignored the MythArc (though we'll see if the last part stays the case).
* ''Series/UpAllNight'':
** In the original pilot, Ava and Reagan work as PR executives (not on a TV show), and Ava is not supposed to be part of the main cast. Then ''Film/{{Bridesmaids}}'' happened, and NBC's willingness to cash in on Maya Rudolph's popularity surge led to the show's first [=retool=].
** The second season dropped the ''Ava'' ShowWithinTheShow, which is cancelled in-universe. This effectively changes the show from a WorkCom[=/=]DomCom hybrid format to being just a DomCom. The switch necessitated changes to the cast, with Missy (a worker on the ''Ava'' show) being dropped in favor of Scott (a main character's brother).
** And then the show was retooled ''again'' in the middle of its second season, switching to a new format with ThreeCameras and a StudioAudience. The plans were to transform the show into a ShowWithinTheShow, where Christina Applegate and Will Arnett would suddenly be transformed into actors (playing themselves) in a sitcom with the same format as the show's original premise. Upon plans of this abomination being made public, both Applegate and the show's original creator quit in protest, and mercifully the show was euthanized by NBC execs before the re-tooled studio-audience version ever saw the light of day.
* The title character of ''Valerie'' was killed off after star Valerie Harper was fired (a rarity then and now) and her place filled by Sandy Duncan, with the name of the series changed to ''Valerie's Family'' and then ''TheHoganFamily''. A rare case of a [=retool=] centered around a SuspiciouslySimilarSubstitute.
* To say that the second season of the 1980s ''Series/WarOfTheWorlds'' TV series used some "[[ExecutiveMeddling creative liberties]]" would be stating it lightly. In the jump between seasons, the plots become ''much'' more DarkerAndEdgier, and the the entire style of the show changed from a somewhat lighthearted, highly cerebral communism metaphor into a dystopian near-future proto-cyberpunk survivalist fantasy (handwaved at the beginning of the second-season premiere by an alien hand gripping Earth and causing darkness). Half the cast either disappeared (General Wilson) or were killed off (Colonel Ironhorse, Norton Drake), the main antagonists of the first season were unceremoniously executed, a new group of aliens took their place as the villains and the setting changed from a mansion to a ''sewer base''. The fans were not pleased.
* For its first two seasons, ''Series/WelcomeFreshmen'' was a sketch comedy show taking place at a high school, with the sketches devoted to a certain theme for each episode. In the third season, the show switched to having a narrative.
* ''Series/WhoWantsToBeAMillionaire'' has gone through countless retools over time on the American version. This includes changing the host from Regis Philbin to Meredith Vieira, adding a clock, changing several of the {{Lifelines}}, omitting the "Fastest Finger" round, etc. The 2010-11 season ''completely'' overhauled the game even further, adding a new payout structure and randomizing both the question difficulty and payouts.
* The first season of ''Series/WonderWoman'', was set during World War II with Wonder Woman battling mostly Nazi or Axis foes and her secret identity was WAVES petty officer Diana Prince. The tone was also a little comedic. When the show moved from ABC to CBS, the show became less humor-oriented, the timeframe moved up to the modern era (the late Seventies), and Wonder Woman's secret identity became an agent of a US intelligence organization called the IADC.
* In its second season to accommodate its full-time move to Nick Jr., ''Series/TheWubbulousWorldOfDrSeuss'' abandoned its half-hour story, replaced the Cat's voice with a less gravelly alternative, ditched the CGI backgrounds and became more of a ''Series/BluesClues''-style kids show.
* ''Series/YesMinister'', after three series, was retooled in an hour-long special which began with Humphrey being promoted to Cabinet Secretary, and then a cabinet reshuffle resulted in Hacker being appointed Prime Minister.
* Here's an example that set a record: the premiere of the {{gameshow}} ''Series/YoureInThePicture'' proved that the game was too awkward to be enjoyable. The second episode was completely different: it consists of the show's host, Jackie Gleason, sitting in a bare set and making a drawn out apology for the failed gameshow. This received much better reviews, so the show was turned into a talk show and renamed ''The Jackie Gleason Show''.
* ''Zoe Duncan Jack and Jane'' was retooled for the second season. The show fast-forwarded the kids from high school and into adulthood (subverting the DawsonCasting trope in the process). The title was shortened to simply ''Zoe...''
[[/folder]]
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* ''AntFarm'' took the kids out of the local school (and by extension the A.N.T. program) and moved them into a boarding school owned by a high-tech corporation... for some reason. China's family got cut from the cast as a result.

* The computer tech show ''The Screen Savers'' that ran on Tech TV then G4 after the merger was retooled as ''AttackOfTheShow''; a more geek and nerd entertainment focused show keeping the same hosts -- at the time, Sarah Lane Kevin Rose and Kevin Pereira as well as Brendan Moran. The user created challenge from the last ''TheScreenSavers'' episode was carried over to the first ''AttackoftheShow'' where the winners were revealed.

* ''Series/McHalesNavy'' moved to the Italian theater of WW2 in its final season.

* One of the most infamous examples was ''Baywatch Nights''. This ''Series/{{Baywatch}}'' spinoff involved the show's resident police officer, Sgt. Garner Ellerbee (Gregory Alan Williams) decide to open a detective agency, being joined by Mitch Buchannon (Creator/DavidHasselhoff) and Ryan McBride (Angie Harmon) and have them deal with street crime. Then when the show proved to be a flop, the producers were inspired by the success of ''Series/TheXFiles'' and decided to replace Ellerbee (who, again, ''founded the agency'') with a paranormal investigator and turn the show into "David Hasselhoff fights aliens, mutants and ghosts".

** The show was originally titled ''Good Morning, Miss Bliss'', and was retooled after a brief cancellation. The school moved from Indiana to California, the name of the series changed, several cast members (including the titular Miss Bliss, played by [[Film/TheParentTrap Hayley Mills]]) disappeared and the focus shifted to the students exclusively.

** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero marked by his CharacterDevelopment from GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are gone. Series 8 has him take more of a backseat to his companion than he'd done previously in the new series (she being retooled from her debut in Smith's final season), but he returns to the show's center afterward. Horror episodes/content still common but the tone becomes melancholy and mature; he spends more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]]. Human companions have lives outside of the TARDIS and the first non-human companion of the revival is introduced in Series 10. Pacing is notably slower, especially in Series 9, which is mostly multi-part stories. With a Doctor conceived as a throwback to those of the Classic Series (especially One, Three, Four, and Six), ContinuityPorn runs rampant, being dialed back in Series 10. Like the Eccleston and Tennant eras, mostly confined to Earth and human outposts.

** Pertwee: A serious, charming aesthete ActionHero Doctor in a TuxedoAndMartini-MonsterOfTheWeek genre mashup show. Companion role goes from being a small group of mixed-sex travelling companions to a primary young, female partner (Liz, Jo, Sarah Jane) and a larger pool of UNIT coworkers who can be drawn in and out of stories as needed. Serial length standardises as six-parters with a four-parter OnceASeries. And everything's suddenly in colour!

** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero marked by his CharacterDevelopment from GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to bereaved professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are gone. Series 8 has him take more of a backseat to his companion than he'd done previously in the new series (she being retooled from her debut in Smith's final season), but he returns to the show's center afterward. Horror episodes/content still common but the tone becomes melancholy and mature; the Doctor spends more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]]. Human companions are allowed lives outside of the TARDIS while the first non-human companion of the revival is introduced in Series 10. Pacing is notably slower, especially in Series 9, which is mostly multi-part stories. With a Doctor conceived as a throwback to those of the Classic Series (especially One, Three, Four, and Six), ContinuityPorn referencing both eras runs rampant, though it is dialed back in Series 10. Mostly confined to Earth; off-world trips are usually to human outposts (space stations, colonies, etc.).

** The most comprehensive and obvious retool was between the 6th and 7th seasons when all three regulars (including the current Doctor) decided to leave at the same time, the show changed to colour from black and white, and the Doctor was given a whole new backstory and exiled to Earth. The show also takes on a much stronger MonsterOfTheWeek format at this point due to the Doctor being stranded on Earth - Hartnell and Troughton would often have general adventure stories with no clear monster figure and themes of exploration or dealing with the culture of a PlanetOfHats, but Pertwee got to fight a new ridiculous [[AttackOfTheKillerWhatever Killer Whatever]] alien (and/or, later, his EvilCounterpart) every month without fail, a much more successful format which hung around for most of Tom Baker's tenure.

** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero marked by his CharacterDevelopment from GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to bereaved professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are gone. Series 8 has him take more of a backseat to his companion than he'd done previously in the new series (she being retooled from her debut in Smith's final season), but he returns to the show's center afterward. Horror episodes/content still common but the tone becomes melancholy and mature; the Doctor spends more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]]. Human companions are allowed lives outside of the TARDIS, while the first non-human companion of the revival is introduced in Series 10. Pacing is notably slower, especially in Series 9, which is mostly multi-part stories. With a Doctor conceived as a throwback to those of the Classic Series (especially One, Three, Four, and Six), ContinuityPorn referencing both eras runs rampant, though it is dialed back in Series 10.

** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero -- a deliberate throwback to Doctors like One, Three, Four, and Six -- marked by CharacterDevelopment from GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to bereaved professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are gone. Series 8 has him take more of a backseat to his companion than he'd done previously in the new series (she being retooled from her debut in Smith's final season). Series 9 is mostly multi-part adventures as he returns to the show's center. Series 10 mixes standalone and multi-part stories; ContinuityPorn is dialed back for the benefit of new viewers. Horror episodes/content still common but the tone becomes melancholy and mature; the Doctor spends more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]]. Human companions are allowed lives outside of the TARDIS, while the first non-human companion of the revival is introduced in Series 10.

* ''Series/DoctorWho'' thrived on this. In chronological order:
** The show was originally pitched as an educational show, and soon retooled to the scifi story it is today. Originally it was supposed to alternate between historical stories set in the past, and scientific ones set in space (which is why the first two companions were a history teacher and a science teacher). This happens as early as the second serial, which features the Daleks (justified as educational by Verity Lambert because of the anti-war moral), and there's some rather half-hearted forced educational moments in later Season 1 serials (such as a scene where Ian and Barbara pause to discuss Roman means of building arches while on the alien planet Marinus), but by Season 2 even that was abandoned in favour of serving up fun adventure stories.
** The personality of the First Doctor got this a couple of times due to EarlyInstallmentWeirdness. He was originally intended to be a TricksterArchetype, the TokenEvilTeammate and constantly getting his friends into trouble, with either Ian or Barbara being TheHero depending on the story. However, it was decided that his character was too unlikeable for children, and the BottleEpisode "The Edge of Destruction" was written quickly to serve as his HeelRealization, after which he became a much more helpful and warm character and quite often TheHero. His final ReTool was hinted at in "The Aztecs" but hit full-force in "The Reign of Terror", and was for him to become a more comical character whose meddling would often get him into weird trouble [[HilarityEnsues with hilarious consequences]]. All of these alterations were carried over to every other Doctor.
** Every single time the Doctor regenerates into a new actor, it comes with changes of the Doctor's personality and show feel. This is almost certainly the only reason ''Doctor Who'' could become the LongRunner that it did. The first regeneration (Hartnell into Troughton) was a relatively small change, but Troughton into Pertwee completely transformed the show's genre, and Pertwee into Tom Baker completely transformed it in a different direction, and again... A basic list, relying on generalisations:
*** Hartnell: A grumpy but good-hearted Doctor in an EdutainmentShow dealing mostly with historical adventure stories and fairly thoughtful sci-fi.
*** Troughton: A comical, silly and straightforwardly heroic Doctor. Show dropped the historical adventures and began focusing exclusively on aliens. The stereotypical Troughton story is a 'base under siege' where a small community of scientists are trying to do something important while some sort of [[PeopleInRubberSuits rubber suit monster]] and/or foam is taking over. Six-part adventures become more common than the four-parters that were the main format of the Hartnell era, but the serial length is still very irregular.
*** Pertwee: A serious, charming aesthete ActionHero Doctor in a TuxedoAndMartini-MonsterOfTheWeek genre mashup show. Companion role goes from being a small group of mixed-sex travelling companions to a primary young, female partner (Liz, Jo, Sarah Jane) and a larger pool of UNIT coworkers who can be drawn in and out of stories as needed. Serial length standardises as six-parters with a four-parter OnceASeries. And everything's suddenly in colour!
*** Tom Baker: A slightly [[ByronicHero byronic]] ManChild Doctor with [[ComicalOverreacting funny mannerisms]]. Show drops the secret agent elements but keeps the MonsterOfTheWeek formula, very rarely dealing with recurring enemies (only two Dalek stories in the whole seven-year tenure). Show also begins taking heavy influences from Film/HammerHorror films, giving it a gothic tone and {{Genre Shift}}ing the show into 'horror' rather than sci-fi, though this is dropped in favour of comedy and pure sci-fi later after a MoralGuardian crackdown. The final season shows a sudden increase in production values, the theme music and visuals are changed, the Doctor starts wearing a more costume-y outfit in order to provide more visual identity and the writing gets dark again, though staying out of horror for the most part. Companion role is streamlined, dropping the coworkers for simplicity and not bothering with male companions for CastSpeciation reasons, focusing on a single young, attractive female character.
*** Davison: A subtle and human Doctor to contract with the previous LargeHam Doctor, whose sonic screwdriver is destroyed as a symbolic attack on some of the lazier Tom Baker writing. Show adds some SoapOpera elements like a large rotating cast of companions and a bigger focus on the Doctor as a vulnerable and emotional figure (where Tom Baker had verged on InvincibleHero) and even going into soap-like scheduling for an ill-advised period. Horror is back on the table and {{Wham Episode}}s and ContinuityPorn are the name of the game (including a whole season of recurring monsters in the run-up to the anniversary special), and a companion gets killed off for the first time since William Hartnell.
*** Colin Baker: An attempted CharacterCheck, much DarkerAndEdgier Doctor; arrogant, violent and verbose. Stories attempt {{Deconstruction}}s of standard Doctor stories and begin to incorporate some engagement with the implications of time travel itself (which is usually just used as a device to get the Doctor into wherever the adventure will happen), like FutureMeScaresMe and TimeyWimeyBall. More stylised, crazy sets and costumes occur. The format changes to 45-minute episodes after it gets UnCancelled.
*** [=McCoy=]: A particularly impossibly wise Doctor who is sociopathic and manipulative, who also happens to be a cheery, funny vaudevillian. After some EarlyInstallmentWeirdness, starts focusing strongly on the companion's home life and personality, as well as continuing the trend of deconstructing the Doctor's relationship with the companion. The story moves in a more arc-based direction, but the show is cancelled here.
*** [=McGann=]: A rather naive and enthusiastic Doctor, aimed at being an AdaptationDistillation of traits from the popular Fourth Doctor. Show begins taking heavy influence from ''Series/TheXFiles'' and is the first to introduce explicit romance between the Doctor and his companion (although Tom Baker and Pertwee had both dabbled in ShipTease). Focus remains on the human companion rather than on the Doctor. (The ExpandedUniverse version of him changes a great deal from this, though.)
*** Richard E Grant: Gallifrey has been destroyed and the Doctor has a whole new truckload of {{Angst}} to be a StepfordSmiler about, and the Master gets to become [[HoYay the Doctor's boyfriend]] with a HeelFaceTurn. Pertwee-era-{{Pastiche}} story, and the companion's personal life continues to be important, but the Doctor contains most of the focus. {{Mythology Gag}}s run thick. Also, it's WebAnimation. {{Retcon}}ned out when a new live action series got a go-ahead.
*** Eccleston: Gallifrey has been destroyed in the Time War and the Doctor has a whole new truckload of {{Angst}} to feel about it. The focus remains on the human companion, and a whole lot of SoapOpera elements are explicitly added to genre mashup levels. Since production values are notably better the monsters tend to be quite self-consciously {{camp}}y, and the science fiction elements are intentionally very soft. The Doctor is also portrayed as almost always knowing the monsters he's up against, a new development. However, the mythology of the series is deliberately shied away from in order to bring in new fans. Also, we focus on time travel rather than space travel; when we leave Earth it's for an Earth space station in the future or the planet humans migrated to and still call Earth in the further future. That part continues into the Tennant era, changing only with series four. There's a theme of humanity's journey that runs through Nine and Ten's years.
*** Tennant: Much more romantic and gentle than Eccleston's Doctor, but also much more brutal and ruthless. Feel of the show remains much the same as with Eccleston due to his extremely short tenure, but takes the focus back onto the Doctor rather than on the companions, and deals with constant themes of morality, loneliness and [[ShootTheDog Shooting The Dog]].
*** Smith: Very similar to Tennant's Doctor, but more childish and less moody. With no prior cast members involved and a new showrunner, the mood changes to a "cosmic fairy tale" theme with a much stronger focus on {{Time Paradox}}es than ever before, and incorporating strong elements of SexComedy. Horror episodes are significantly more common during this period, and MythologyGags to the Classic series, purposefully avoided before, become thick on the ground. We also see more alien worlds -- they're still HumanAliens, of course.
*** Capaldi: Another CharacterCheck Doctor: A bonkers PragmaticHero -- a deliberate throwback to Doctors like One, Three, Four, and Six -- who receives extensive CharacterDevelopment, evolving from a GrumpyOldMan and DeadpanSnarker questioning his morality (Series 8) to a CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to a bereaved professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are dropped. Series 8 has the Doctor take more of a backseat to his companion than he'd done previously in the new series, as ''she'' was being retooled from her debut in Smith's final season. Series 9 is almost all multi-part adventures as he returns to the show's center. Series 10 returns to a mix of standalone and multi-part stories. Continuity with previous stories and eras is strong but by Series 10 has been heavily streamlined to lessen ContinuityLockout issues. Horror episodes and content remain common as the tone becomes significantly more melancholy and mature, with the Doctor spending more time dealing with the fallout of his actions, [[WhatTheHellHero being chewed out by others]], and struggling with his needs for companionship and a MoralityChain [[WhoWantsToLiveForever when he will never have anyone forever]]. Human companions are allowed to live lives outside of the TARDIS, while the first non-human companion (Nardole, a HumanAlien / cyborg) of the revival is introduced in Series 10.
** The all-but-abandonment of "pure historicals" (episodes with no science fiction elements other than the Doctor and his TARDIS himself) and their replacement with much rarer "pseudohistoricals" (stories where the Doctor will travel back in time to fight an alien) was an early attempt at this, as historicals were proving much less popular with audiences than the PeopleInRubberSuits. The first story to contain pseudohistorical elements was "The Chase" (which contained a short WackyWaysideTribe sequence involving Daleks on the Mary Celeste), and the first true pseudohistorical was "The Time Meddler" - the reveal that it was another time traveller causing the mayhem was a shocking twist to an audience expecting a CostumeDrama with HornyVikings, [[SeinfeldIsUnfunny but pretty much expected now]]. The last pure historical of this era was "The Highlanders", although the Peter Davison story "Black Orchid" also fits the strict definition of this story type.
** The most comprehensive and obvious retool was between the 6th and 7th seasons when all three regulars (including the current Doctor) decided to leave at the same time, the show changed to colour from black and white, and the Doctor was given a whole new backstory and exiled to Earth. The show also takes on a much stronger MonsterOfTheWeek format at this point due to the Doctor being stranded on Earth - Hartnell and Troughton would often have general adventure stories with no clear monster figure and themes of exploration or dealing with the culture of a PlanetOfHats, but Pertwee got to fight a new ridiculous [[AttackOfTheKillerWhatever Killer Whatever]] alien every month without fail, a much more successful format which hung around for most of Tom Baker's tenure.
** The Fourth Doctor's personality went (inorganically) through three different archetypes depending on who was producing his run, as each writer envisioned a different tone for the show. His first personality, during his GothicHorror-influenced era, was a CreepyCute NightmareFetishist ManChild who occasionally struggled with big moral decisions but was also very unpredictable, possessing BlueAndOrangeMorality. His second personality, during his LighterAndSofter-cum-DenserAndWackier era, was PlayedForLaughs - much more of a {{Cloudcuckoolander}} and also much more of a NiceGuy (dipping into FunPersonified at times), although also more of an AttentionWhore and more awkward to deal with. His third personality, when the show decided to get DarkerAndEdgier again, made him philosophical, [[ByronicHero Byronic]], dignified and quite morbid, developing some {{Chessmaster}} qualities and dispensing with a lot of the childlike aspects of his character. Broadly, his taste in hat colour indicates which personality he's going through at the time - a brown hat for [[CharacterizationTags goth!]]Four, a green hat for funny!Four and a red hat for old!Four.
** The [[LastOfHisKind wiping-out-from-all-of-existence of the Time Lords]] between the show's 1989 cancellation and its 2005 resurrection might also be considered a retool. (Actually, the introduction of the Time Lords counts as a bit of re-tool in itself. Originally the Doctor simply came from a mysterious alien civilization, with no more details offered.)
** The revival of Gallifrey in the 2013 50th Anniversary Episode is also one of these - it almost immediately preceded the Eleventh Doctor's regeneration episode, and helped end AnArc that had been pushed as long as it could have been and now only served to hold the character back.

*** Smith: Smith's Doctor is very similar to Tennant's Doctor, but more childish and less moody. Show's mood changes to a "cosmic fairy-tale" theme with a much stronger focus on {{Time Paradox}}es than ever before, and incorporating strong elements of SexComedy. Horror episodes are significantly more common during this period, and MythologyGags to the Classic series, purposefully avoided before, become thick on the ground. We also see more alien worlds - they're still HumanAliens, of course.
*** Capaldi: Another CharacterCheck Doctor: A bonkers old man -- a deliberate throwback to Doctors like One, Three, Four, and Six -- who receives the most extensive CharacterDevelopment of the new series, evolving from a GrumpyOldMan and DeadpanSnarker questioning his goodness (Series 8) to a CoolOldGuy in a partnership of equals with a long-tenured companion (Series 9) to a bereaved professor/grandfather figure to a new one (Series 10). ''Most'' of the romantic hero elements are dropped. Format-wise, Series 8 has the Doctor take more of a backseat to his companion than he'd done previously in the new series, as ''she'' was being retooled from her debut in Smith's final season. In Series 9, the show format changes to almost all multi-part adventures while her role is reduced. In Series 10 the format returns to a mix of standalone and multi-part stories, and continuity with previous stories and eras is strong yet streamlined to lessen the risk of [[ContinuityLockout lockout]]. Horror episodes and content remain common as the show's tone becomes less whimsical and more melancholy, with the Doctor often dealing with the fallout of his actions and brooding over his moral successes and failures. The human companions are allowed to live lives outside of the TARDIS, while the first non-human companion (Nardole, a HumanAlien / cyborg) of the revival is introduced in Series 10.

** Eleven's arrival is also quite the retool; the showrunner changed too, so we got a change in tone, and the entire old recurring cast goes away.

* The original series of ''Series/DoctorWho'' thrived on this. In chronological order:

*** Capaldi: Another CharacterCheck Doctor resulting in a bonkers old man. The Doctor takes more of a backseat to his companion than he'd done previously in the new series and ''most'' of the romantic hero elements are dispensed with. There's more PracticalEffects and the pacing is slowed slightly, with longer and more developed scenes and a less convoluted storytelling style.

** Twelve's arrival seems to be another shakeup; the companions are allowed to live their lives outside of the TARDIS and the first two episodes seem to be showcasing a much more ambiguous Doctor similar to some of the classic Doctors, with the Doctor getting much more physical in encounters similar to The Third Doctor as well as displaying a much more pompous, snarky and self-righteous attitude similar to the Sixth Doctor.

* When ''Series/LaverneAndShirley'' moved from Milwaukee to Los Angeles. They took their dad, Lenny, Squiggy, and Carmine with them.

* ''Series/TheTorkelsons'' was retooled into ''Almost Home'' after the first season, having the mother move to Seattle as a nanny, and jettisoning two of her kids for the kids she was nannying (one of whom was played by a young Creator/BrittanyMurphy.)

* ''Series/{{Mannix}}'':
** In the first season (1967-68), the title character worked for a detective agency called INTERTECT that utilized state-of-the-art (for its time) computer equipment to solve crimes. However, Mannix generally disregarded the computers and the agency's rules to solve crimes his own way. Creator/LucilleBall (''Mannix'' was the last show produced by Creator/DesiluStudios) decided that the computers were over most viewers' heads and asked to have them worked out of the show. This turned Mannix into a more conventional detective series. The [[UsefulNotes/{{Fonts}} font]] used in the credits were based on IBM's corporate font of the time. That font and the theme music were about the only things that transitioned over into the new version of the series.
** In season one, the ''Mannix'' [[http://www.youtube.com/watch?v=CF_49tWPNWA&NR=1 title card is literally a computer card.]] From season two and beyond (1968-75), [[http://www.youtube.com/watch?v=vyZL_3bxD68&feature=related with the better known title card with the shifting letters.]]

* The 2007 ''Series/FlashGordon'' remake was retooled during a mid-season hiatus to combat highly negative fan reactions. The MonsterOfTheWeek format was abandoned in favor of an arc-based storyline, Flash's BlackBestFriend was dropped from the cast and much more screen time was spent on Mongo in general. It didn't save the show from being canceled, although many fans thought it got better after the retool.

* ''Series/{{JAG}}'': The first and, to a lesser extent, the second season focused primarily on action packed pre-trial field investigations, while the third and later seasons joined that formula together with an equal amount of courtroom and office drama in the stylistic vein of ''Series/LALaw''.

* The British cop show ''Bergerac'' had a bizarre final series in which the lead character relocated to France and became a private eye, to little consequence.

* ''Series/TheElectricCompany1971'' returned in the late 00s as [[Series/TheElectricCompany 2009 an updated version]] -- filled with rapping kids with superpowers fighting bad guys, MindControl plots, and other elements that reek of ExecutiveMeddling. Even Joan Ganz Cooney, the creator of ''Series/SesameStreet'', didn't think it was all that good.

* ''Series/TheElectricCompany'' returned in the late 00s as an [[DorkAge updated]] version -- filled with rapping kids with superpowers fighting bad guys, MindControl plots, and other elements that reek of ExecutiveMeddling. Even Joan Ganz Cooney, the creator of ''Series/SesameStreet'', didn't think it was all that good.