In Canaan the vice president cannot call off a B-2 about to bomb the president.
Played for Laughs in D.Gray-Man. Several of Komui's wacky series of robots, the Komurins, seem to lack a function to abort any given command. It only seems that the Komurins can prioritize certain commands, as seen when Komui has one go after Allen rather than have her sister subjugated to its augmentations. By the time Komurin-Z, a walking Mazinger parody, first appears, Komui finally seems to have gotten the point and installed a "terminate command" option.
In One Piece, Spandam is given the normally admiral-only privilege of initiating a Buster Call, where ten large battleships led by five vice-admirals arrive at a location and bombard the place with explosive cannonballs until the place has been leveled and no survivors remain. Spandam accidentally signals the Buster Call to the island where he lives and works, and no command exists to rescind it. From then on, the Straw Hat Pirates' main objective shifts from defeating Spandam to holding up against the Marines and getting off the island.
In the first Alien film, Ripley sets the self-destruct for the Nostromo in order to destroy the alien when fairly certain that she can safely get to the escape shuttle. However, along the way, she finds that attempting to do so will put her directly into the path of the alien, so she tries to go back and shut down the self-destruct. But, by the time she goes through the ridiculously-complicated abort process, the point of no return has already been passed.
Bulworth has the title character lay a hit on himself (he's suicidal). For obvious reasons, he cannot call off the hit. He manages to call it off eventually, but only by unknowingly dating the one girl who was actually assigned to assassinate him, and accidentally telling her about the mistake.
''Dark Star's plot centers around an active bomb that refuses to drop from the bomb bay and cannot be shut off.
In The End, Burt Reynolds plays a man with a terminal disease who wants to kill himself; he gets another man (Dom DeLuise, a psychiatric patient, to help him. Near the end of the film he decides not to kill himself, but DeLuise's character continues to try to kill him. He thinks it's a No Matter How Much I Beg situation even though the man never told him that.
This is the entire plot of the 1964 Henry Fonda movie Fail Safe.
Intolerable Cruelty: the lawyers find they cannot reach the killer they hired to kill one's ex-wife (they're in a divorce, and the hit was dicovered was ordered when it turned out her former husband was poor, and therefore so was she. When another ex-husband Goes Out With A Bang leaving an unchanged will that leaves everything to her, they try to cancel the hit). So they end up trying to stop the killer themselves before it's too late.
The Odd Job: which was originally a half-hour comedy episode starring Ronnie Barker and David Jason, later made into a film starring Graham Chapman. Same basic plot - guy decides to end it all by hiring a hit man to kill him when he doesn't expect it, but then finds he has something to live for after all and desperately tries to find the guy so he can cancel the contract. He succeeds, but then falls foul of one of the assassin's booby-traps.
In Parting Shots the main character has a hit called on himself (as he has cancer and plans to kill everyone who ever wronged him before having himself murdered to leave the Love Interest with his life assurence money). On discovering he's recovering he tries and fails to call off the hit. Luckily the hitman misses and kills a hated dicatator (and also framing himself for the protagonist's murders). As a result the protagonist gets off scot free and the hitman becomes a hero.
In Tomorrow Never Dies, The Royal Navy launches a Tomahawk missile to destroy a terrorist arms depot. They quickly find out that there are nukes at the camp. But are unable to abort the missile requiring James Bond to go in and remove them.
The Star Chamber revolves around a group of judges who hold tribunals for criminals who have escaped justice in the courts and who delegate Vigilante Execution to the mob. A major plot point is the inability to call off a hit on a couple of lowlifes when they turn out to be innocent of child-killing.
Film - Western Animation:
In WALL•E, Directive A-113 orders Axiom to prevent humans from attempting to recolonize Earth. The only way to countermand the order is for the captain to get out of his chair, walk to the control panel, and press the "manual control" switch. It Makes Sense in Context.
Famous examples of this are from The Bible, in reference to the kings of the Medes and the Persians. The Medes and Persians had a law that if the king's ring was used to seal a proclamation then it could not be undone, not even if the king changed his mind.
Daniel and the Lion's Den is probably the most famous. King Darius made a decree that anyone who prayed to a God other than him for a period of a week would be fed to the lions- and sealed it with his ring. Daniel continued to pray, and despite Daniel being the King's favorite, and the King not wanting to go through with it, Daniel was still thrown to the lions.
Esther is another example. The Persian King gave Haman his ring, which Haman used to seal an order authorizing on a certain date the murder of all the Jews and the seizure of their property by the killers. When the King discovered Haman's plot he had Haman executed, but could not undo the order. So he wrote out a new order allowing the Jews to kill anyone who attacked on that date. The Jews then slaughtered their enemies who attacked them.
In the Game of Thrones book, A Song of Ice and Fire, the dying King Robert tried to call off the assassination he ordered on Daenerys Targaryen, but his message didn't go through. While the assassination does fail, the attempt does a lot to motivate Dany to invade Westeros and retake the throne.
At the end of the third season of Castle, a major blow is dealt to whoever ordered Beckett's mother killed when his favorite hired gun is killed. The one who did that killing sent off a bunch of info to a fourth party so that there would be no retaliation against Beckett. Unfortunately, that mail arrived too late to prevent a sniper taking a shot at her.
Chuck: In Chuck Versus The Business Trip, an assassin known as "The Viper" is known for going dark after receiving instructions and making it impossible to retract an assassination order, meaning that Decker cannot call off the hit on Morgan.
Doctor Who: The Doctor almost gets Davros to do this in "Genesis of the Daleks." The Doctor has control of Davros' life support system and tells him to give the order to destroy the proto-Daleks or else he'll turn it off.
Davros: This is Davros. Elite unit seven will go to the incubator room. All survival maintenance systems are to be closed down. The Dalek creatures are to be destroyed.
Doctor: Tell them the order cannot be countermanded.
Davros: This order cannot -
Nyder knocks out the Doctor from behind
Davros: This is Davros, this is Davros. My last order is cancelled, repeat, cancelled. No action is to be taken.
An episode of Seven Days had terrorists give a bomber wing an order to destroy an American base (supposedly overrun). Since Frank temporarily lost his memory when traveling back, the good guys didn't contact the bombers until they were past the official point of no return. They had to put the commander's pregnant wife on the phone to convince him.
In an episode of Star Trek: Deep Space Nine the stations auto-destruct sequence (which was set up by the Cardassians prior to the start of the series) is set off. They call on Gul Dukat, the former station head, to disable it. He gives the turn off code, only to find out that his superiors had disabled his authorization to call it off since the only reason he'd have to call it off is if the station had been overrun by Bajoran resistance fighters and were forcing him to do so.
Star Trek: The Original Series episode "Let This Be Your Last Battlefield". Rather than let Commissioner Bele take the Enterprise to the planet Charon, Captain Kirk orders the computer to activate the ship's Self-Destruct Mechanism. During the last thirty seconds of the countdown, Kirk tells Bele that once the countdown passes five seconds the computer cannot be stopped from destroying the ship. Bele gives in at the last second (literally) and Kirk aborts the self destruct sequence.
A Star Trek: Voyager episode features a sentient torpedo who's been sent to destroy the enemy. En route a peace is declared, but the command to the torpedo to abort the mission is garbled such that the confirmation code can't be immediately accessed. If the torpedo destroys its target, it'll set off another war. Our heroes must solve this problem.
Part of the intended ending for the original "Van Buren" Fallout was a nuclear missile launch that couldn't be stopped about to eliminate what remains of human life After the End and the PC would only be able to stop a number of missiles based on their repair skill, and must choose which places are struck (alternately, you could have blown them up in the silos, but take yourself with them).
The Fallout: New Vegas DLC "Lonesome Road" has an attempt at this by Ulysses. He prepares some nuclear missiles to launch. After the player defeats him, it turns out all you can do is change the target; you can't prevent the launch, so you must either launch the missiles at the NCR, the Legion, or both... unless you rescued ED-E, and order the bot to perform a Heroic Sacrifice.
Averted in Tribes: Vengeance, where Mercury's hit on Daniel is called off just before he takes the shot.
In Sword of the Stars Human and Tarka ships can't be given new orders while they're traveling FTL. If a Human or Tarka player signs a Ceasefire with another race while one or more of their fleets are en route to the other race's colonies they will continue on and start a battle.
On Adventure Time, Ice King hires a hitman to get Finn and Jake. Only he misunderstands the concept of hitman (he thinks he's just going to hit them), and when he realizes that the hitman is actually going to kill them, Ice King tries to stop him, but the hitman proves implacable.
In Avatar: The Last Airbender, Zuko hires "Combustion Man" to kill Aang. He later has a change of heart, but even when he offers the assassin additional money to call off the hit, the silent man shoves him away and continues to pursue Aang.
Parodied in the Camp Lazlo episode "Taking Care of Gretchen". Sampson offers to "take care of Gretchen". Lazlo accepts, thinking "take care of" means pamper. After watching a mob movie, he realises what Sampson meant and tries desperately to stop what he now thinks is a hit, only to find he is too late.
They parody this in Family Guy. Peter accidentally orders a hit on Lois, so he goes to the mobster that contacted the hit man to get the hit called off, but just before the mobster can do it, the mobster himself gets killed in a hit.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.