You cannot edit a payment in 3Shape LMS. You have to delete it, then re-create it. This article will show you how to delete payment.
*Note: payments processed with Wepay can be refunded for x days after being processed. Once that time has passed, you will need to delete the payment and refund the client directly. Deleted Wepay payments are NOT refunded to the client's credit card.
1) Go to Billing > Payments >Find payment > Actions gear > View/Edit
2) Click "Delete"
3) Click "OK"
4) Type "DELETE" then click "Confirm"
*Note: DELETE must be in all caps