Diagnosis
You changed the rate category for installation &v1& on &v2&.Backbilling has been established for this installation. The currentbackbilling period starts on &v3&. You are not permitted to change therate category within the current backbilling period.

Procedure
If you wish to change the rate category, you can do so at the start ofthe next backbilling period. You can end the backbilling period earlyby executing a final billing.