SAP Message AC591 - Rule &1 cannot be deleted

Diagnosis
Rule &V1& cannot be deleted because it is still used in at least oneaccounting transaction.

Procedure
You can only delete rule &V1& if it is no longer used in any accountingtransactions. Therefore, you should check the transactions in whichrule &V1& is being used.
Note: You cannot delete rules in the SAP name range (01 to 89).