Originally Posted by
djohannw
... Should I consider this as a sign that the upgrade already cleared on that segment? ....
Select the new seat and check you itin -- are you in R fare class and does the seat assignment stick? If so you are in.
BTW the "schedule change" was probably the TA's way for handling the upgrade notification they received from UA. In general when you use a TA the notices go to them and it is the TA's responsibility to notify you. That's the way communications are handled when you use a TA unless the TA tells UA otherwise.