You cannot change the status of the sample line to &1

What causes this issue?

You attempted to change the status of a payment scheme sample line to
&V1& either manually or using a BOR method. This is not permitted. You
can only make the following changes:
If you change the status using a BOR method:
' ' as default value
'1M': Changed manually by a workflow item after periodic billing
'2M': Changed manually by a workflow item after interim billing
'1R': Changed automatically by a workflow item after periodic billing
Abrechnung.
'JS': Changed automatically by switching from joint invoicing to
individual invoicing.

System Response

The attempted change is not made.

How to fix this error?

Enter a permitted value according to your situation.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.