I know there was a version of Changes (from the Greatest Hits) that surfaced time before the album came out (or close to the release date)..
is that a pre-release mix or just the 12" version? or do I have wrong info? lol
plenty of exclusive mixes have appeared on european-only promos.
there is no changes pre-mix or alternate mixdown... you may be thinking of the old o2 "promo" website versions with some added instrumentation here and there for the fuck of it.