SAP Message >4209 - Maintain the reversal indicator

Diagnosis
You have maintained either the field "Reversal date" or "Run ID", buthave not set the reversal indicator. To be able to identify and thenreverse a transfer posting run that has already been carried out, youmust set this indicator.

System Response
The system cannot continue processing.

Procedure
If you want to reverse a transfer posting run that has already beenexecuted, set the reversal indicator. Alternatively, delete the entriesin the fields Reversal date and Run ID.