If you want to make changes to invoices that have already been "Paid", you will need to unallocate the payment from the invoice first in order to make it editable. You can find the steps to unallocate a payment from an invoice in this article: Unallocating a Credit Note or Payment from an Invoice.
Unallocating a payment from an invoice will not delete the payment. The payment will still be in your Teachworks account and can be allocated to an invoice again in the future.
You can find a list of unallocated payments by following the steps below:
Click on "Billing".
Click on "Payments".
The “Unallocated” column will have a numerical value if the payment has an unallocated balance.
If you don't plan on allocating the payment to a future invoice or refunding it and you'd like to delete the payment entirely, you can follow the steps below:
Click on "Billing" and then click on "Payments".
Use the date filters and/or the "Search" field on the right-hand side to locate the payment you want to delete.
Click on the "View" icon to view the payment.
Click on the "Options" menu at the top-right of the payment.
Click on the "Delete" option.