You’ve been using computers for quite some time, I’m guessing. You’ve worked in dozens, scores, maybe hundreds of different programs. And in every one of them, when presented with buttons that say OK and Cancel, their behavior is generally consistent. OK commits whatever changes you just made and Cancel discards them. And by “discards them” I mean leaves you in the same exact state as before you went into that dialog or form and started making changes.
That is, unless you’re working in Centricity.