How about for an existing points reservation? For example, I have a points reservation in Tallahassee for an FSU football weekend. Since that time, I have earned a Reward Night Certificate. I would like to exchange one of the points nights to use the certificate. Normally I would cancel the reservation and re-book. But since the hotel is sold out, I don't want to lose the room I already have reserved. Is this something that the average telephone reservations agent can handle or should I play it safe and save the certificate for another time?