Dropping nights from your current reservation will not effect your discount. However, the title of your post states "change to room only". If you have a package booked now and want to change to room only, the package would have to be cancelled/refunded and room only booked, requiring a new deposit equal to 1 night's room rate + tax as money paid toward one cannot be applied to the other. With that said, if your pin code is expired, guest services would have to make the change in order for you to keep your discount as a regular reservation CM wouldn't have access to expired discounts. If you are just dropping nights from your current ressie, that can be done without any problem. Also, if your pin code is expired and you were wanting to book AoA for a few nights under that discount, that would not be possible as that would be a new reservation and the discount wouldn't apply. But if your pin code is still current, you could book AoA if there is availability.