I've booked a Reward flight from DFW-LAS next Thurs. night, and I just found out I have to work in DFW Fri. morning. There are no reward flights available on Friday, so I think my options are limited to the following:
- Upgrade the reward flight to First for 20k miles, which would let me on the Fri. flight
- Change the dates of the reward flight for 9 months out and hope I go back to Vegas this year.
- Redeposit the miles (or change the city) for $100.

My question is this - I'm on the last flight on Thursday night. If I 'accidentally' miss the flight, what happens? Would they let me fly standby on Friday? If so, is there a charge? And would it be a problem that I couldn't fly standby until noon on Friday?

Thanks in advance.