Payment Order line status can be different from the Payment Order Slip status. The payment order line status can be "Approved", even if the payment order slip status is "Draft". It depends on the line status whether it is possible to make changes on the relevant line. All fields, except for the Status, of the lines in Approved and Cancelled statuses are non-editable. Records in Paid status are also non-editable, and the status of such records can only be changed by the system. The Paid status is not listed as an option of Status field.