In my office in Florida I have, I think, 30 manuscript piles around the room. Some are screenplays or comic books or graphic novels. Some are almost done. Some I'm rewriting. If I'm working with a co-writer, they'll usually write the first draft. And then I write subsequent drafts.
I never edit the songs that come out. And they tend to come out as a whole. The closest thing I have ever done to editing them is just cutting out a verse, but never rewriting lyrics.
I'm not someone who comes onstage and says, 'I'm rewriting this now.' I don't think it's fair to the writers or the director, or the other actors.