Retconning in movie franchises is more common than audiences might realize. To retcon something means to change the retroactive continuity of events or characters within a franchise. It could be as simple as a character's origin story shifting slightly, to entire plot arcs being undone in the blink of an eye. There are many reasons for retconning, from issues like actors being unavailable to correcting heinous character creations. Retconning itself is not necessarily bad, but it can be.