Change "I am your father" into "Obi-Wan killed your father" as shot originally. Discard everything after that scene, including of course the prequels and sequels (but keep Rogue One and Andor because this is now for grownups). Rewrite and reshoot everything else based on the premise that Vader and Anakin are two separate people, as was originally intended. Make a prequel about the relationship between Anakin, Vader, and Obi-Wan, in which Vader‘s face is that of David Prowse. And establish Darth as his first name ffs, not some stupid title or degree or what.