Originally Posted by
Kacee
In other words, until the PNR is split, since SHARES can't process upgrades on a multi-passenger itinerary.
If that's an intentional change in the process, it doesn't make much sense. Freeze the whole upgrade process because there's one multi-pax PNR?
This is one of those inherent SHARES limitations (like inability to clear dynamically) that has plagued UA's systems ever since the merger.
Yes, the inherent limitation still exists, but they've layered something else on top as a workaround.
I won't argue that the change is reasonable, but I have observed multiple cases for which it seems to be the explanation. There are also scattered reports here of people not being immediately split on check-in despite agreeing to it.