It seems that director JJ Abrams knew Rey had to be descended from someone important in Star Wars, he just didn’t know who. Star Daisy Ridley revealed that Rey’s parentage kept changing through all three films in the Skywalker trilogy—and it wasn’t until Star Wars: The Rise of Skywalker was already being made that…
Source: io9 – Rey’s Parentage Was Up in the Air Until The Rise of Skywalker Entered Production