First time going to Gencon this year.  I purchased two Gencon tickets (one of them is for my son for a HS graduation present) on my credit card.  I set them for pickup at Will Call.  About a week later, my bank (unsolicited) sent me a new credit card (with a different number) and forced me to cancel my old number.  As I read more about the show, I decided to pay the $10 per ticket and have them mailed to me, rather than wait in line at Will Call.  I could find no place to update my card number and when the website tried to charge it to my old credit card number, the transaction was denied, as that card has been cancelled.

Whether I have to stand in line to pick up my tickets or get them mailed to me isn't all that important, but what I fear is that this same sort of snafu is going to happen when I attempt to register my wishlist for events on 5/19.  By the time I deal with a card update, some of the events we're interested in may be gone.  Is there a way to update the credit card number associated with my badges now?  Could I cancel my existing badges and just buy new ones (on the new card) somehow?  Thanks in advance.

IIRC, when you go to pay for events, they ask you for CC information each time, so you can correct it there.  Also, email customer service and ask them to change your card.

You can change your credit card information when you purchase event tickets or a badge.
You could ask Customer Service to cancel your badge so you can repurchase it and update your Credit Card information, but We do not recommend it if you are getting event tickets as you will be able to update then.

We cannot change you credit card manually. 

Mike Boozer
Customer Service & Event Team Manager
Gen Con LLC
 

You have 2 hours from when your queue number/wishlist is processed to checkout/complete payment before the events in your cart are released back into the wild.