I actually JUST did this. I had 192 banked points that HAD to be used. I posted them on the RENT board and bada-bing-bada-BOOM they are gone. Made the reservation just the same as I would any other points. I just made sure I let the renter know that reservation could be changed ONLY if change request was available and that points HAD to be used by (specific date).
Very EASY!!!