Originally Posted by
jrl767
exactly
that said, cue the nay-sayers who will advise OP about potentially violating corporate travel and/or ethics policy (submitting a false receipt with an expense report), even though the difference between expensed Y and flown F came out of OP's own pocket
speaking as one who has traveled on business for 10 employers over ~40 years, and who has done this more than a few times, I have only had a handful of inquiries from people in the approval/accounting/audit chain about a ticket number mismatch, but *never* has *anyone* rejected my answer: "Ticket was reissued when I paid for an upgrade out of personal funds"
in the old days of paper tickets, UA was far better than other airlines about returning the original passenger coupon (receipt) after an exchange at the airport or a city ticket office
It's more about your company's policy than anything else.
At some companies they have been fine with me booking F and reimbursing me based on a screenshot that shows the cheapest Y flight.
And some companies expressly prohibit paid upgrades, even if you pay for them yourself. Luckily I've never worked at one of those.
And most have policies somewhere in between.
Personally I would be ok violating a policy like this, but then again I've never really valued my job that much. My approach has always been that if they don't like it I can go work somewhere else. But I would not necessarily recommend that approach to anyone else, without knowing their situation.