No, the company is not required to pay out the accrued PTO first. They do have to give you a chance to use it--they can't simply take it away--but so long as they do give you a chance to use it, they can set reasonable deadlines on its use and/or require its use before moving to a different PTO plan. Many people treat their PTO as if it's deferred income or a bonus cashable later, but it's not: PTO *is* "paid time off* and its purpose is to let the employee take time off without losing income. As long as you are given the chance to use it, that is all that is required.