Originally Posted by
laxsnaogg
I've done it (but as with everything these days, you need a CS that knows the "rules"). As long as the rate on your existing reservation is refundable, they can change the rate and keep the suite upgrade attached to it.
I did it and my suite upgrade stated it was still booked but a few weeks later i called the hotel and it wasn't. Luckily I called the hotel to make sure everything was in order. But I was able to call the Diamond line and they were able to fix it for me even with the hotel being sold out!