If you'd like to refund a customer for a single item or just for part of their order (e.g. just the tax for tax-exempt organizations), you must first calculate with the refund amount is. Then follow the steps below:
Go to Orders > Order Management and select the location the order was placed in
Click on Old Orders and find the order
Click on Refund and enter the amount you're refunding
Click on Submit Refund
If you need to make an additional refund on the same order, you can go back to the order and click on Refund again and you will be shown the remaining amount available to refund.
Once you submit the refund, the customer will receive an email confirmation. To edit what the email confirmations look like, you can go to Settings > Email Confirmations and scroll through to the refund emails.
Please note that all refunds are final and cannot be undone.