Meaningful Rename / Live-Action Films

• Near the end of Air Force One, the pilot of the C-130 declares that the plane is changing call sign from Liberty-2-4 to Air Force One. Since the call sign Air Force One is only used by a plane carrying the President this is effectively his way of announcing that the President is safe.
• Back to the Future Part III: Seeing Doc Brown's tombstone that said he had been shot in 1885, Marty speculated that perhaps another Emmett Brown had lived in the town at the time. Doc immediately shot that theory down, explaining that the Browns hadn't come to Hill Valley until 1908 and at the time they were known as the Von Brauns. He goes on to explain that his father changed the family name to Brown during the First World War.^note Due to anti-German sentiment among the American public as well as the general benefits to being a WASP, many German-Americans in the early 20th century Anglicized their names.
• The Clash of the Titans remake has King Acrisius changing his name to Calibos after he was turned into a demon by Zeus. In the original film, Acrisius and Calibos were two different characters.
• In City of God, Lil Dice gets the new name Lil Ze from a religious practitioner, who states his new name will change his fate.
• In Guardians of the Galaxy Vol. 3, a flashback reveals a young Rocket chooses his name "Rocket" after he sees one blast into outer space and starts dreaming of flight with his friends. Later in the movie, Rocket realizes he is indeed a raccoon from Earth, and calls himself Rocket Raccoon.
• The Holy Office: Luis de Carvajal changes his name to José Lumbroso (=the one who burns in his faith) after King David tells him to in a vision.
• In Kamen Rider × Super Sentai: Super Hero Taisen, Captain Marvelous reintroduces Bio Hunter Silva, a foe that the Bioman team faced in the past. However, he's been rechristened Rider Hunter Silva, as he's now used to hunt and defeat Kamen Riders.
• In Kung Pow! Enter the Fist, Big Bad Master Pain decides (very temporarily) that he wants to be good, so he decides that he'll go by the name "Betty". The Chosen One quickly points out that Betty is a girl's name, causing Master Pain/Betty to flip out.
• In the first entry of the The Mighty Ducks trilogy, Coach Bombay has his first few encounters with said team when they were only referred to as the bureaucratically-assigned District 5 since they had No Budget for anything beyond skates and sticks. It was only after Bombay wrangles a sponsorship so that they could afford proper equipment, uniforms, and rink time that they became known as the Ducks.
• Monty Python and the Holy Grail: After King Arthur brings a shrubbery to the Knights Who Say "Ni!," they suddenly change their name to the Knights Who Say "Eki Eki Eki Zakung Zoop Boing and Zowie Za."
• In Muriel's Wedding, Muriel changes her name to Mariel (with an A) to symbolize her new life away from Porpoise Spit.
• Oblivion: Julia Rusakova makes a point of presenting herself as Julia Harper when she and Jack go back to La Résistance's bunker. When the Trojan Prisoner gambit is being worked on, she enters a capsule with a Meaningful Name on it. See Chekhov's Gun for details.
• The townfolk of Refuge in Purgatory were all outlaws, murderers or prostitutes, but while there they shed their old, famous names for nature-themed ones. Glen, Lamb, Rose, Ivy, etc. It's part of an attempt to put all that behind them, apparently. During the final few scenes, they use their famous names again, since they think they're about to go to Hell anyway.
• Susan from A Safe Place (1971) renames herself Noah after the Magician's magic box, which is painted like Noah's Ark when she first sees it. The Magician even pulls a rainbow out of it.
• In Samurai I: Musashi Miyamoto, a Buddhist monk takes it upon himself to train talented swordsman Takezo as a samurai. When Takezo completes his initial training, the monk congratulates him and gives him the more samurai-appropriate name of Miyamoto Musashi.
• Scott Pilgrim vs. The World: When Scott Pilgrim goes to the Chaos Theater again, he renames Young Neil to just Neil to signify his growth into his role. Interestingly this probably says more about Scott's Character Development than Young Neil's.
• This is notably averted in the 1968 film The Shoes Of The Fisherman in that Cardinal Kiril Lakota announces he would continue to use his given name of Kiril upon his election as Pope. This not only marks the first time that a non-Italian was elected Pope since the 16th century, but also the first time since the 16th century that a Pope continued to use his given name upon election.
• In Star Trek IV: The Voyage Home, McCoy paints the name "HMS Bounty" on the Bird of Prey captured in Star Trek III: The Search for Spock.
• Happens with Sith in Star Wars.
  • Anakin Skywalker is renamed Darth Vader and is spoken of as a different person.
  • Count Dooku, having left the Jedi to join the Sith, had already become Darth Tyranus.
  • Palpatine/Darth Sidious.
  • Kylo Ren, formerly known as Ben Solo.
  • The rulers of Naboo take a new name when they ascend to the throne, which is how Padmé Naberrie became Queen Amidala. Even after her time as queen is over, she's still Padmé Amidala.
  • In The Force Awakens, Resistance pilot Poe Dameron escapes the First Order with help from a defecting Stormtrooper whose designation is FN-2187. Instead of calling him that, Poe decides to name him Finn. For the rest of the trilogy, Finn uses his new name to make it clear that he's no longer a Stormtrooper.
  • At the very end of The Rise of Skywalker, Rey, who had been revealed to be the granddaughter of Emperor Palpatine, took the last name of Skywalker after getting the blessing of the Force Ghosts of Luke and Leia.
• In The Three Musketeers, Athos tells his former wife that the Comte de la Fère (his real name) is dead; he uses anecdotes from his past by claiming that they happened to a friend of his.
• Titanic (1997): Rose was born Rose Bukater. She changed her last name to Dawson, to signify her love for Jack, and to forever renounce her old life as a repressed rich girl.
• In Transformers: Revenge of The Fallen, when one of the ancient Primes betrayed their beliefs, the other Primes stripped him of his name and he has forever since then been known only as The Fallen.
• The titular hero of Young Frankenstein at first tells everyone that his name is pronounced "Fronkensteen" to disassociate himself from his infamous ancestor Victor and his legacy. Then in a crucial moment of the movie, he shows that he has accepted his heritage by insisting: "My name is FRAN-KEN-SHTINE!"