No matter what kind of credit or refund you wish to give, the first step is always to create a credit on the family's account. This is sort of like "store credit" - They will be able to use this credit to pay for any registration in any current or future seasons, and it never expires.
If you've created one or more Withdrawn programs as described in our season/program setup guide, go to the Family's profile page and click Modify Registration next to the player's registration, then move the player to the Withdrawn program. This will automatically create a credit.
Go to the Family's profile page and click Family Financial to go to their financial ledger. Find the invoice that you would like to apply a credit to, and click the Admin Credit button on it. This will bring up a window where you can choose how much to credit them, and what kind of credit to apply. A "Checked out" credit will be applied to the invoice immediately, so it cannot be turned into a refund later. A "Not checked out" credit will not immediately affect the family's balance, instead they will be able to use it for a future registration, or you will be able to refund it back to their credit card.
Optional: Use the credit to refund the family
To actually refund a family so they receive the funds back to their card, you will first need to give them a Not Checked Out credit as described above. Once you have done this, you will see the credit as a "Not checked out" item on their Financial ledger.
Under this credit, you will see a button called On-File Refund. You can use this button to process a refund in the amount of that credit.