I want to buy extra generic tickets, but also want my money back if I don't use them. How do?

You can turn them in at the convention for system credit and they deduct the 10% restocking fee. I cannot remember the last date for a cash refund, but there is a fee that they take out of about 10% for refunded tickets prior to the convention. It should all be in the event file that is available on this website.

According to this generic tickets will only be refunded for system credit and the fee for event tickets is 5% and it says that you can do so at the kiosk on site up until 4:00 PM on Sunday. I am not sure about online.

REFUNDS

• All refund requests prior to the show must be made by the end of day on June 16, 2019 at 11:59 pm (Eastern). Absolutely no badge cancellation requests will be honored after June 16, 2019, 11:59 pm (Eastern). (Exchanges can be made on site starting July 31, 2019.)
  
• Cancellations and refunds requested before the June 16th deadline will be processed during Gen Con Customer Service hours.
  
• Refund requests received prior to the June 16th deadline will be issued a refund and credited back to the original credit card or system credit used for purchase, less any administrative fees.
  
• All badge refunds are subject to a $10 administrative fee. All event and generic ticket refunds are subject to a 5% administrative fee for the total sum of tickets refunded. There are no exceptions.
  
• All refund requests must be made by the purchaser via mail or email (see Contact Info below).
  
• Refund requests must include the first and last name of the attendee, Gen Con account number and email address associated with the account. Badge types and Game IDs, along with a description of the items to be refunded is greatly appreciated (i.e. a 4-Day badge and eight generic tickets, or three Saturday badges and three True Dungeon tickets, Game ID#________).
  
• Only event tickets can be refunded on site. Badges are non-refundable and non-transferable.
  
• Event ticket refunds will be managed at the Customer Service kiosk and will only be refunded to the person whose name is on the ticket or to the original purchaser. All tickets are only good for the year that they were purchased.
  
• A valid government-issued photo ID and a Convention badge are required to process any type of ticket refund on site.
  
• Event specific ticket refunds/exchanges must be requested at least 30 minutes prior to the start of the event. Refund/Exchange requests received after that time will not be honored.
  
• All event specific ticket refunds are subject to a 5% administrative fee for the total sum of tickets refunded. There are no exceptions. Refunds will be made back to the original form of payment.
  
• Generic tickets will only be refunded as a system credit. There is no cash refund on generic tickets. There are no exceptions. (System credit can be used to purchase badges or tickets for any future Gen Con. It is non-transferable, non-refundable, and does not expire.)
  
• The last day to receive a generic ticket or event specific ticket refund is Sunday, August 4, no later than 4:00 pm, at the Customer Service kiosks.
  

You can return tickets online on your Schedule or Transaction pages and selecting Return Tickets (it'll then let you choose which tickets). You can return them online until June 16 for a full system credit. Or you can email Customer Service for a cash refund with a 5% fee. After that date, you may only return them onsite at Gen Con and there is always a 5% fee.

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Alec Usticke, Fans of Gen Con Facebook Group

Right now, while tickets only exist on your online account, you can return them online.

After they get printed (which starts June 17th), you have to turn in the physical tickets in order to refund them. Otherwise there'd be nothing to stop you from using them.

I'm not sure about e-tickets.

Since you're talking about turning in generics at the end of the convention, they will obviously be paper tickets and after June 17.