Purchasing Water Park tickets with AP discount

[luvallprincesses]

We will be using our APs for the last active day on June 11 and not renewing them. Am I able to buy tickets to Typhoon Lagoon using the discount on that day (once we know the weather will be okay) and use them the next day? Or do they have to be used while the AP is current? We're undecided as to whether we might want to go on June 11 or 12.