Thanks for all your advice. I agree that it is better to leave it blank - however I was hours away from checking in when I had to cancel.

I was able to solve my problem by calling Ambassador Customer Service who gave me a "one time only" swap with a new certificate that I will get in the mail in 2 - 3 weeks. This will enable me to cover my trip without having to use CC to trade my current certificate.

Thanks for all the help.

Bob