Are you trying to retcon Rey’s parentage or more like just edit it out of the movie?
Edit it out. I may end up leaving the cave scene intact. But then there’s the scene where Kylo tells Rey that her parents were nobodies and “sold [her] for drinking money.” The scene comes off like hasty, cheap dialogue and left many in the audience (including myself) feel it was lacking.
If her parents really are nobodies or if JJ Abrams changes his mind in Episode IX, finding out the parents are nobodies in this movie adds nothing to The Last Jedi’s story. It’s part of Rian Johnson’s message that Jedi can come from anywhere, but the parentage reveal (or lack of one) feels cheap for those hoping for answers. I do plan on keeping the part of the scene where he says “you’re nobody, but not to me” because of the tentative connection that Kylo and Rey have and her temptation to the dark side.