US Airways Dividend Miles - switching FF# after upgrade clears?

I've been upgraded for my US flight tomorrow using my DM#. I haven't checked in yet. Can I switch to my United FF# without losing the upgrade? Would I be better off using the check-in kiosk to change this, or an agent at the ticket counter? I tried to do this previously with the 800# and was told I'd lose the upgrade if I switched numbers. Anyone have experience with this, and know if it's possible? Thanks!

U will lose it.

From the Preferred Upgrades T&C (http://www.usairways.com/en-US/dividendmiles/preferred/upgrades.html):

If you've received a Preferred upgrade, you cannot replace your Dividend Miles account number with another program’s account number unless you choose to be downgraded to Coach.

If you've received a Preferred upgrade, you cannot replace your Dividend Miles account number with another program’s account number unless you choose to be downgraded to Coach.

But I'm sure the OP is curious, as I am, does anyone have first-hand experience with this -- does this really happen in practice?

But I'm sure the OP is curious, as I am, does anyone have first-hand experience with this -- does this really happen in practice?

From experience, if you talk to an Agent, they will downgrade you. If you do it via the kiosk, it will process just fine and keep the upgrade. I have noticed that sometimes the miles still post to US instead of UA, even if you change the # at the kiosk.

I've had success with the reverse. Getting a United upgrade due to status there, then switching the number on-line, and getting US credit.

Long story short: if you try and screw the system then prepare to be screwed yourself. Seems fair to me.

I had 15k miles deducted for the upgrade from my account
This one was not even intentional.
I was not sure which one to credit to and the upgrade had cleared.

I switched to my MP# and took the downgrade in order to earn segment credit on UA. Got to shoot for that 1K status!