Log in to your admin side of Payflow by navigating to manager.paypal.com, and logging in using your credentials.
Click on Report tab, and choose Daily Activity under Standard
Place in the date in which the transaction was placed, and click on Run Report button on the bottom
Under TRANSACTION ID, select the Delayed Capture ID of the transaction in need of a refund, and copy it.
Now click on the Virtual Terminal tab and select Single Transaction
Under Tender Type choose Credit Card (or whichever pertains to the card that was used (most likely Credit Card)
Under Transaction Type choose Credit
Now paste the Transaction ID you had copied previously, and place it under the Original Transaction ID
Click the Submit button
Check over and verify that all fields look correct, and click the Submit button
The Result screen should show a Response Message on the top as Approved.
This now completes the refund process in PayFlow
Please Note, when selecting the transaction to credit, make sure you select the correct transaction that you want to credit. You are unable to perform a credit on an Authorization. You must select the Delayed Capture transaction to credit.