Originally Posted by
CIT85
This should be straight forward. Just call and ask to drop the dates in question. You already hold the nights and award does not involve potential rate changes. If you don't call in advance and waited until you check in, then you'll have to deal with getting points back.
Apparently it has worked differently on the SPG side where the requirement is new inventory has to be available for a change to be facilitated. There is concern on that board that even though Marriott has said changes will be allowed if you are holding the reservation (not date, but say to a lower points amount) and call in over there most people do not think Marriott will follow that policy even though MR has done this for years.