I am looking at purchasing the current 3 days for the price of 2 days ticket special for my trip next month. I am currently not sure of my specific park related plans for my final day in the DLP area as we are planning some other sightseeing on the final day and not sure if we will have time to go back to the parks before closing. If I purchased the 3 days for the price of 2 day tickets would I be able to upgrade this ticket for the cost difference if I decide later I want to add the 4th day to my ticket. I know at Disney World I would be able to add on days to the ticket, but I don't know how or if you can add on days to a DLP ticket.