Upgrading 2 Day Hopper to 3 Day?

[justkeepswimmin]

I purchesd a 2 day hopper for my dd (the rest of us have APs but due to her turning 3 1/2 way through our AP year, we just got her a regular ticket). Turns out we will be in DL an extra day and I will need the 3 day ticket for her. Is there anyway to upgrade the ticket now to get the advanced purchase price ($139) or will I have to wait and do it when we get there and pay the gate price ($169)?

We purchased her 2 day ticket from ARES travel.