We will soon be traveling to DLR and have already purchased the CityPass tickets. We may wish to extended our DLR days. Will we be able to "upgrade" our 3 day parkhoppers to a 5 day or even maybe to a DVC-discounted annual pass? If anyone has details on how (if) this works, I'd be grateful. I'm not sure what kind of "trade in' value the city pass parkhoppers even have.... thanks.