Originally Posted by
Xyzzy
I think most of us do what is ethically right so we don't threaten our jobs. That rules out shenanigans like spending more company money on airline tickets than we have t
. With that in mind, purchasing an economy ticket via the corporate agent and then calling UA to up-fare to F using your own credit card is a generally accepted way to pay for an upgrade yourself.
There is one scenario where that would not work without a caution: if the corporate agent purchases fully flexible Economy fares, I think that the upfare to First puts it in the non-flexible category. I guess the OP can decide if that is a risk that is acceptable.