Retconning

Found this interesting article about something called retconning or retroactive continuity , which is "deliberate changing of previously established facts in a work of serial fiction."

Probably the most famous retconning was the Han Solo and Greedo encounter in Star Wars. Marvel Comics did this recently with it's One More Day story arc...Apparently, Marvel's editor-in-chief decided that the marriage of Peter Parker and Mary Jane should never have happened because he wanted Peter to be single again! Interestingly, J. Michael Straczynski, the writer, was against the idea of retconning Peter and Mary Jane's wedding.

J. Michael Straczynski talks about OMD...
JMS states that "there’s a lot that I don’t agree with"