I did it!
Last Month!
I had October 31st Tickets 'cause my eldest sons best friends were moving and I didn't want him to mope around during Halloween. At the last minute, their parents (twins) changed their minds.
Needless to say my son no longer wanted to be away during Halloween, which worked out well since the whole free dining/value season thing for Oct. 4.
I exchanged my tickets for Oct. 7th. Here's how it went down.
1) I called 407-wdisney and told them something had come up and they refered me to the tickets people.
2) 1-407-566-4985 Disney TIcket Help
They told me to write a letter including my address and the credit card number I used to purchase the tickets
but not to include the expiration date. , enclose the tickets and send them to:
WDW TIcketing
200 Celebration Pl
8th Floor
Celebration, FL 34747
I sent them certified although they didn't think it was necessary.
It took a couple of weeks but I got the new tickets, no problems!
Hope that helps!