Originally Posted by
ORDnHKG
As this didn't happen on UA metal flight, not to mention, UA often sell mix awards, which means as long as there is one leg in 3 class F, while the rest of the legs are in C or Y, you will still be charged as F award the whole way, which also means no miles are due not unless this is the only leg in OP's itinerary.
The $500 cash from TG is more than enough for compensation, as this wasn't a paid ticket or award ticket issue from TG.
This advice is just wrong and has zero understanding of international transportation law.
An award is simply the method of purchase of a revenue ticket. There are conditions associated with the purchase, like not earning points (this is a feature even of tickets purchased by cash). Once the ticket is confirmed it is legally no different from another confirmed ticket (excluding non-statutory aspect). All ticket allow an individual to voluntarily downgrade a leg, allowing a party to travel when desperate. Similarly when purchasing a ticket through the award method, an individuals can choose to book into a lower class when the class code is not available in the award tickets class. This feature means an individual can decide to voluntarily write off part the ticket's value, in order to make travel possible (rather than increasing the class code of the ticket).
This is very different from involuntary downgrades. In this case the individual has not decided to write down the value of the ticket, and accordingly the airlines are responsible for the lowered value. Two airlines are responsible for this, either (a) the airline of transport, or (b) the airline issuing the ticket. In some jurisdictions there are additional statutory penalties on top of the contractual aspects, most noticeably the EU.