Thought I'd ask this question in the UA forum since it involves a UA flight. I currently hold a paid-economy roundtrip ticket, to an international destination. The upgrade chances are looking very, very slim at this moment so realistically I'm expecting to sit in coach (undesired). Fortunately, a pure award for this flight in First Class is available. My question is, can I use both tickets on the same flight. That is, at the gate, turn in an economy-class boarding pass and an First class boarding pass. (obviously I'll physically be in F and let the coach seat go vacant). I called UA and keep getting different responses such as its okay to buy 2 different seats but must be in the same cabin, or no, or sounds okay. I strongly prefer to turn in the coach boarding pass so I can get the Qualifying miles for this trip, rather than reschedule. Any suggestions as to how I can do this? Thanks again in advance.