Step 1 Search the purchaser in the Relationships Tab
Search by any of the fields available and click the purchaser’s name
Step 2 Click on the ‘submit’ icon under Purchase Orders
Step 3 Select View Payments
Step 4 Select Details for the transaction
Step 5 Select Voided from drop down list and press "Yes, Change"
Tip: A refund is still required through your payment gateway provider.