Something like this happened to me a couple of years ago. I had a return ticket SFO-DFW. Once I got to DFW our client insisted I flew back to SFO with them (on their expense, thank you). I called Delta and explained the situation. The agent was very friendly when she told me that they couldn't refund anything, but suggested I hang on to the ticket for a year (that's how long it was valid), because "you never know if it comes in handy".
/Pete
[This message has been edited by L-1011 (edited 07-19-2001).]