Revisionism
From Wikipedia as of today:
"In fiction, revisionism is the retelling of a story
or type of story with substantial alterations in
character or environment, to 'revise' the view
shown in the original work. Unlike most usages
of the term revisionism, this is not generally
considered pejorative.
The film Dances with Wolves is a revisionist
Western because it portrays the Native Americans
sympathetically instead of as the savages of
traditional Westerns, which have been criticized
as racist. Similarly, the novel Wicked by
Gregory Maguire is a revisionist account of
The Wonderful Wizard of Oz , which portrays the
Wicked Witch of the West fighting for what she
believes is right, and the Wizard as a ruthless
dictator of Oz."
See also another Wikipedia article's Revision History.