retcon

[ ret-kon ]
/ ˈrɛtˌkɒn /

noun

a subsequent revision of an established story in film, TV, video games, or comics: In an awkward retcon of his origin story, the hero’s parents survived the attack but suffered complete memory loss.

verb (used with object) ret·con·ned, ret·con·ning

to later revise (an established element of a fictional story): The writers retconned the origin of her powers, newly attributing them to alien ancestry.

Origin of retcon

First recorded in 1980–85; a shortening of retroactive continuity