Yep, you can upgrade but make sure you have whoever bought the ticket with you. I believe they refund the ticket and sell a 'new' one. You can't/don't pay the difference on the day.
Is this done through a ticketek outlet? If someone is an adult that uses a concession ticket to get in, how would the AO staff actually know. I’ve never seen them check ID’s.
On iPhone using BigFooty.com mobile app