I have some upcoming travel on UA, which I want to credit my flights to US (for CP qualification). I am also silver on UA, and wanted to see if it was possible to take advantage of that for E+ access.

I know on PMUA you used to be able to give them two frequent flyer numbers, but I'm not sure what the post-SHARES situation is. If I can't provide two frequent flyer #s, should I provide my UA # at checkin, then change it to US at the gate after selecting E+? Should I just use my US # but try showing my silver card at the gate?

Any suggestions would be appreciated. The flight is at an off-peak time so I'm thinking there is a good chance of E+ (or dare I say even F?) being available.