But, don't be surprised if they say no, because they are non refundable. It's always worth giving a shot because truly I've not heard of anyone who did not get a refund. It would be interesting to know how many have been told "no refund".
When I purchased my ticket I had to agree to terms that said no refunds, transfers, etc. That doesn't mean that calling and talking to a CM won't help. It's always worth a try.
We had to reschedule our trip due to unexpected surgery, and I was able to get a refund on all of our MVMCP tickets, just a few days ago. They were very nice.