Originally Posted by
br2k
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On a non-refundable ticket, what are the options (if any) to cancel the return flight and keep some value - i.e. being able to take the same or similar return flight later?
Yes, it is possible but the ticket will get repriced and needs to be within the fare and routing rules of the original ticket. This is not a simple item to predict and generally you will have to consult with UA to get an answer to a specific set of circumstances.
The easiest case is a simple change the return date -- generally this is a simple repricing. Note the return needs to be completed with 1 year of the original purchase date. May also have to beware of max stay limitations.
Changing the return's O/D things get much more complicated.