Answer
To issue a partial refund for a payment submitted by a parent, head to the Accounting section.
Once in Accounting, search for the parent. Once the parent is found, click the blue "View Transactions " option to the right of his/her name.
Then, please find the payment to be refunded, and to the far right of the payment, click the three dots to find the 'refund' option.
When processing the refund, you will have the option to make a partial or full refund.