If the ROF is a pass (and interception, catch, or incomplete) it can be reviewed. If after review, it was determined the QB's was down prior to throwing the pass, then the interception (or catch or incompletion) would be nulified. The down & distance would be corrected to reflect the actual result.
If the QB was ruled down when he actually wasn't, the subsequent whistle (and stoppage of play) would not allow replay to get involved.