Payments can be deleted form Participant Management. First you need to select a participant and scroll down to Payment History. In payment history all payments belongs to this participant will be listed.
Click to the See Details button and the Payment Details window will be open. You can see all the details about this payment with Delete Payment button.
Click on the Delete Payment button a confirmation message will be displayed if you click on Delete Payment button the payment will be deleted but the service booked for this payment will be kept by the system.
Please note that this will only delete the payment from the MeetingHand and your event. If this is an online payment you need to delete or refund it form your own payment gateway.