SAP Message /BON/AG_MNT017 - Payment method for agreement &1 could not be updated

Diagnosis
You have changed the payment method for the trade spend assigned torebate agreement &V1&. The rebate agreement cannot be changed in SAP CRMas it is assigned the status to be settled in ERP or settled
.

System Response
The system does not change the payment method of rebate agreement &V1&.Other rebate agreements that are assigned to the same trade spend can beupdated if their status allows it.