You can edit an invoice before the invoice has been paid. To edit an invoice follow these steps:
Find the invoice in the Invoice table and click the pencil icon that says "Edit" when you hover over it.
Change any invoice details that need to be changed. If you've added or removed events from the calendar and want to update them on the invoice you will need to select the "Add Lessons" option and retrieve the lessons again to update the invoice with the lesson changes.
Click the "Save" or "Approve" button to save the changes.
If you want to edit an invoice that has already been paid you should generate a new invoice or issue a credit note to capture any changes.
If you’d like to make changes to a paid invoice, for example if you’d like to change the service that’s selected on the invoice, you can unallocate the payment/credit associated with the invoice by following these steps to make the invoice editable: Unallocating a Payment from an Invoice
Once you’ve made your changes, you can allocate the payment/credit to the invoice again by following these steps: Allocating Credit or Unallocated Payments to an Invoice