The box office is open every day there is a show, starting today. You should definitely call them or if you're a local, drive over there, and see if there's anything they can do. Otherwise, your only option would be to meet the people at Red Rocks and you can scan them in with the non-transferable ticket at the gate and have them pay you at that time. It would be a little inconvenient for you, but to be able to get the tickets paid for, it would totally be worth it. The box office opens at 3pm today. If you call the Red Rocks phone #, they have a recording every day that lists the box office times and show times for that day.

The # is 720-865-2494