I've always wondered: Is there a way to add multiple coupons/vouchers to a reservation at the time of booking? I'm trying to get rid of some Hertz courtesy vouchers that expire in the next few weeks and can't figure out how to add them all to the reservation. Usually when I've added them, it allows one to be added but then still shows the balance to be charged, even though more than one can be stacked. When I've needed to have it adjusted, I have waited in line at the location and they always have been able to add the additional coupons, but it would be nice to have this done in advance to really take advantage of Gold service.