You will not lose the cert. as it is issued annually after you have paid the annual fee (i.e. once you pay the annual fee you earn the cert.). As was said, technically you have to use the AMEX to purchase the ticket, but I'm sure there is a way around this. Because the cert. is issued upon renewal, if you have one that is valid there should not be a fee due soon, so you could always just hang on to the card until you redeem and then cancel.