Sorry for the general AA question- I figure this forum is most knowledgable.

I bought a round trip ticket DFW-LGA and was planning on staying in NY 2 weeks. However, unexpectadly I lanaded up flying JetBlue to SEA in the middle of the trip.

Now, I'm in SEA and trying to get home. What is AA's policy for changing my LGA-DFW return to be from SEA-DFW instead? Is it more worthwhile to buy a totally new ticket?