Are there any issues with park reservations when upgrading a ticket to an AP? We have an upcoming trip during which we will upgrade 6 day PH to APs. I've made park reservations for the trip but debating when we should do the upgrade. We will need to book an additional day or two at the end of our trip. Concerned I may lose existing reservations when we do the upgrade so wondering if we should wait to until Day 6 of reservations to do the upgrade.