You could do what I did, I modified my reservation online and took the $50 coupon off and replaced it with a $25 coupon. I would rather lose $25, than $50. Esp since one Person reported that the agent would not honor. Either way keep us posted how it works out.
Shoot wish I would have read this first, I just booked and paid for it to take my chances. What is the $25 coupon code in case in the end I can at least use that when I am talking to the agent. If you don't mind sharing that is.