Go to your inspection grid by clicking on Inspections -- View Inspections. Choose your desired inspection and click on Actions -- Payment Information. (Or click on the $ icon if you have icon view enabled)
Click on the void link next to the payment authorization (or refund if the void link doesn't show up).
This will immediately void the card transaction.
In the new Payment interface, scroll down to the Payment History section and click on the Void option:
If you have any questions about this process please let us know! You can reach us by chat, email at firstname.lastname@example.org, or phone at (800) 700-8112.