Originally Posted by
keeton
This.
Don't call and cancel - just don't show up for your return flight. This way, you don't have to explain anything to anyone. Any credits due will automatically be put in your DL "wallet".
Yes, you are gaming the system but you can usually get away with it once. If you do it repeatedly, the DL revenue protection unit (the infamous RPU) will notice and take action.
Also, if you are a non-US citizen, make sure your non-returning does not violate any immigration law, which could be a MUCH bigger issue.
In my cases it has never been gaming the system. Plans changed where I needed a car, or plans changed and it was substantially cheaper to just drive back then it was to change the ticket, or buy a new one way ticket. I can see if you did this once a week something would happen, but if you do it once or twice a year or so I am pretty sure someone would need to understand that plans do change. It is like buying a ticket to a concert, not going, and getting hit with fines because you left the seats empty.
Under the way some people have described this you do this once, and you are in serious trouble. I guess plans are never allowed to change.