Partial Refund of an Order (After Funds Captured)

To provide a partial refund of the customer's payment for an order (e.g. you aren't able to source one of the requested items) and you have already captured their payment funds yet. [However, if you have not captured their payment funds, go here instead; or if you need to cancel the entire order, go here instead.]

You would probably want to send the customer an email first, before doing these steps, informing them of the reason for the partial refund (unless you've already in communication with the customer regarding it).

Go to the "Details" section (click heading to open the section), click "Edit" link and then update the quantity for the product which you are unable to provide. Click [SAVE] before continuing. This should update the "Total Due" at the bottom of this section to a negative/refund amount (also adjusting sales taxes). If the refund is not due to a change in the products, then ignore this paragraph and continue.

Go to the "Payments" section (click the "Payments" heading to open the section) and find the "PAYMENT LOG" table to determine if the customer has already paid for the order:

In the bottom-right corner of the PAYMENT LOG table is a small form where you can usually void or credit the payment amount.
Check to see if the "CREDIT - Adjustment" option is available in the drop-down list. For some payment methods (e.g. PayPal), a partial refund is not possible, only a full refund).
Enter the dollar amount to be refunded into the unlabeled amount field above the drop-down list.
Select the "CREDIT - Adjustment" option from the drop-down list and click the "Apply" link.

Above the "Payments" section is a Notes area. You might want to enter a note about the refund and its reason under the "ORDER NOTES" tab. The customer can see the "ORDER NOTES" as well. If you don't want the customer to see your notes, then put them under the "PRIVATE NOTES" tab in the Notes area. Click [SAVE] to record the note.

Update the order "Status" if appropriate (and [SAVE]).