just finished a rental in DEN via this. It was a National rental, of which I'm exec elite. The 3rd party was Carlson Travel, which I think is based in Minneapolis. If u have any frequent renter w/co's under 25, it would be best option to rent from these when you scroll thru the choices. I'm over 25 but when I wanted a car for Sunday nite pickup it was not available. So I made it Mon early AM-same aomunt of time/miles redeemed. Then I called the location direct, they had my rez and I explained the situation to them, upon which they switched me to a Sun nite pickup as seeing my status. Plus I got to go to the EE section to choose my SUV. Only thing I had to do was paperwork as the voucher didn't allow that, but it was pretty quick. Maybe this won't help you if you don't have status but if you do it's worth a call.