I was told last year after I purchased my tickets that there were no refunds and I was not allowed to trade them for a different date. The situation worked out for us as we were still able to work it out so that we could attend on the date we purchased tickets for. But the CM I spoke to was very clear that they could not be traded. Perhaps if I had called back and asked a different CM I would have gotten a different answer.
I agree, though, that if you would post the date your tickets are for, you'd probably find someone on the DIS that would purchase them from you. Ebay is also another good option, but you would have to pay the auction fees.