When it says that "no residual value will be given" if you change to a cheaper flight, does that mean that the value of the underlying ticket stays the same in this scenario, or does UA pocket the residual value from the ticket once the change is made?
For example, if you change from a flight that had a fare of $250 to one that was $200, do you earn PQP based on the $250 fare or the $200?
Or if the new flight later gets cancelled or has a significant schedule change, do you get $250 back or $200?