Upgrading from 2 day to 3 day tickets at check in?

[Eddie512]

so we bought 2 day/ 3 park tickets, since we are driving and I have no idea what time we'll will arrive. Had planned to,relax at resort on arrival day. BUT, if we get there early and want to hit the parks, can I upgrade to a 3 day/ 3 park ticket at check in? If I'm doing the math correctly it would only cost an extra $100 or so for the 5 of us... could that be right or am I missing something?

 

[damo]

Each hotel has an attraction desk that should be able to help. However, you can just use that ticket for that day and upgrade at guest services inside the park before you leave.