On iS there is a procedure, which I can't remember, so long as it's exactly the same photo and you're just changing the processing. However, I read that years ago and the iS forum is a total nightmare to search.
If you want to replace some at iS, you could throw yourself at the random mercies of whichever CR person gets your ticket and hope they know the procedure, else they'll likely just tell you it can't be done.