1. retcon - Noun
2. retcon - Verb
retcon (plural retcons)
A situation, in a soap opera or other fiction, in which a new storyline explains or changes a previous event or attaches a new significance to it.
retcon (third-person singular simple present retcons, present participle retconning, simple past and past participle retconned)
To employ such a device.
Even with that retcon, Noble 6 is still a force to be reckoned with. Source: Internet
In 2002, with the publication of the Wildstorm (DC) comics, Harmony Gold officially decided to retcon the Robotech Universe. Source: Internet
Marvel already told Scarlet Witch and Quicksilver's origin story, but Marvel could retcon Magneto into being their real father in WandaVision. Source: Internet
Claremont expressed dissatisfaction with the retcon, stating in 2012: "We’d just gone to all the effort of saying, 'Jean is dead, get over it,' and they said, 'Haha, we fibbed.' Source: Internet
However, the core of his story could be where a proper retcon could build on to make him a sympathetic killer, which has worked for franchises like with Jigsaw/John Kramer and add a new level of brutality. Source: Internet
None of this really matters in the scheme of the original narrative -- unless some future story turns this new retcon into canon. Source: Internet