How long after first use do you have to upgrade to Annual Passes?

[toddbushman]

Anyone know if you use a multi-day park hopper how long after the first use you can still upgrade to an Annual Pass? Do you have to do it within the 13 or 14 days after first use, or could you wait several months as long as it is in the same year? i.e. if you went in June and decided to go again in December could you upgrade those June multi-day park hoppers to Annual Passes in September? I know it's a longshot, but figured someone on the board would know.

 

[bumbershoot]

It has to be within its useable time. Has to have a day left on it (could be that day, the last day) and has to be within the 14 days.