Yes, you can cancel/delete or refund a ticket purchase or offline ticket sale by following these steps:
Step 1) From the Event Ticket Dashboard, click on Transactions.
Step 2) Click on the Operations icon.
Step 3) Click the blue "Refund" button.
Step 4) You will have two options when you issue a refund or remove an offline ticket. You can either remove the ticket sale and keep the total the same, or you can remove the ticket and also adjust the total amount sold.