Originally Posted by
flyer777lr
Wait until you arrived at your destination and change your return Flight into W class , UA will charge you only the fare differential between paid and W Fare plus a possible change Fee , mostly not since its only an upsell ..... good luck !
Si that is how it seems to me from the fare rules. But we know that field test is the only methodology with guaranteed result. I will attempt this from PEK and report back.