You can manage ticket orders by clicking on the manage ticket orders icon from the event page. This is where ticket orders can be viewed, refunded, and rejected.
Viewing orders will list the number of orders made by each member, the ticket price paid, as well as any additional fees.
A notification will appear in the news feed as well as via e-mail when a user requests a refund (as shown below). You can issue a refund by clicking on the refund icon of each individual order. When issuing a refund, a reason can be selected from the drop down menu.