We visited Carowinds this past week and I upgraded to a Platinum Pass but still had my old Gold pass and when the Parking-teller scanned the card it rang up, as he told us, "a Kings Island Platinum pass", but he let us through anyway. I then had to go to customer service and for a while they tried to contact Kings Island to see what they should do, to no avail, and they ended up giving me a 2013 Platinum pass that let me into the park. They did advise me that I might have to go through the same thing again at Kings Island though.