I just found this online. I will call MS to confirm, but wasn't sure if anyone else experienced this...
"In the past, you could upgrade most Disney park tickets to an annual pass as long as you did it within fourteen days from the first day of use, even if there were no days left on the ticket. At one point, you could even upgrade when you got home as long as you still had the ticket and you did it within the same month.
Here are the new rules:
-Tickets must be upgraded within the first seven days of use. That means if you first use the ticket on a Monday, you'll need to upgrade it by the close of business on Sunday.
-Tickets must have at least one day remaining on them.
-Tickets must be upgraded in person.
While you can buy a new annual pass at your resort's concierge desk, you'll need to go to a ticket booth or Guest Relations in the park or Downtown Disney to upgrade your Magic Your Way tickets to an annual pass. I just did this at the will-call booth in the Magic Kingdom a couple of days ago and it took all of five minutes. Make sure you have your photo ID with you. You AP start date will be the date you first started using the Magic Your Way ticket, not the day you upgraded to an AP."