I bought a combo ticket through Undercover Tourist with 2 day park to park and 1 HHN entrance. No date on the HHN voucher. My questions are: 1. Does Halloween night sell out and if so, how can I change the voucher over to a hard ticket to make sure we get in? 2. Can you explain early access to HHN and is it necessary to get the full experience of HHN? Thanks!