We are going to DL this week, and I have purchased 2 day parkhoppers for my kids and the 3 day Southern Cal. pass for my husband and myself. In the past, I was able to easily convert a one day parkhopper to the So. Cal. AP the day that I entered using the parkhopper. I want to do that this time as well, and convert all the different tickets to the cheap So. Cal. AP on our second day and pay the difference. All the tickets I bought cost less than the cheapest AP. Someone recently told me you have to convert the ticket on the first day or you can't convert it to an AP?? I cannot find any confirmation of that. Does anyone know? Thank you. We are going during AP blackout days which is why I bought the parkhoppers in the first place.