This is what I do, although I think now you have to click "change reservation" and it will show what room rate you have it under. You can click the change button and then you can look at other discounts and everything. I do this for every single trip since I tend to book so far in advance, it is so much easier than canceling and rebooking, or calling. I have changed room categories, resorts, or even just the discount. I've gone from rack rate to general public to an AP discount (my husband says it makes his head spin with how much I watch for deals and room rate differences lol). It only takes a minute, and if there is a price difference (for room only reservations) you just pay the difference; if there is a credit it will just be applied to your final bill and you don't owe anything. As a note I've only had to pay anything when upping to a different resort level or to a CL room after discounts have come out, if you stay in the same category this obviously doesn't apply.