Originally Posted by
ozflier
Assuming there are seats available on other airlines, do the above canx pax get seats in the same class or downgraded.
Upgraded passengers (regardless of the form of upgrade) are supposed to be rebooked in their original class of service, even when being rebooked onto another United flight. The exception would be where they schedule a new flight as a replacement (eg, UA839 -> UA1745 the next day) in which case upgrades should stick.
Occasionally there are reports of people being rebooked onto a different airline in their upgraded class of service, but they are rare and probably simply come down to human error when looking at the booked class.