I basically never check the rename boxes (except for an obvious typo), so no. It doesn’t change ACs, but it does change relationships unless they already have a specific credit set.
IMO that is a bug because it is not consistent with what happens to non-relationship AC. It should act the same by preserving old name as AC.
That’d be undesirable - most of the time I’ve renamed I definitely don’t want to keep the old name for rels, but I do for ACs. Having two separate options for them would be fine though.