Sure. That would work. You'd just let the resort know and they'd combine all 5 nights into a single booking and then you'd call HH USA and get the remaining points credited.

If you didn't do it that way, TTT103 is correct when he / she said that you'd have to cancel then re-book. Thing is, if you do it a few months out, i.e; quite a bit ahead of your cancellation policy deadline, the points return instantly, every time!