Originally Posted by JGfromOC

Another option is to print out the price of the lowest economy fare. Book your ticket at the lowest upgradeable fare and then use miles to upgrade (if you don't want to risk not getting the upgrade at the gate). This way your company can reimburse you for what they would have paid and then you're stuck with the balance - but at least this way you avoid the $250 change fee and have everything cleared up front.

That said, I've only ever done this on domestic flights in the U.S., so not sure how that all would work for an international flight.