The rules state any published (non discounted) rate is eligible to use a Chase RC credit card certificate (you get 3 every year at renewal). Unless you are using corporate rate or AAA rate you can upgrade. The certificates post to your account and they deduct at check in. 1 certificate is good for up to 7 nights. You might save $50-100 per night or up to $200-350 in others such as NYC or New Orleans. Good credit card benefit, certainly not a gold or platinum benefit.