Not that this is what you're asking about, but I have gotten airlines to let me do something like this during irregular ops.

Years ago I was flying SJC-LAX-TUS on DL on the day before Thanksgiving. I got to LAX to find that my flight had been cancelled and the only alternative was delayed by several hours. I figured that I could rent a car one-way, drive to TUS, and get there before I would arrive by air even if everything went right from that point on. I went to the GA and said "I'd like to miss my flight to TUS and drive there instead, but I still want to use the return flight. Can you cancel my LAX-TUS flight in such a way that I can do that?" The LAX GA was only too happy to do that--one fewer disserviced pax to deal with. (Then I called the DL 800 number to make sure my record had been annotated correctly before I left the secured area, since I didn't want any surprises on my return!)