SAP Message 8I807 - Reverse quantities not possible for &1 as Excise invoice already exists.

Diagnosis Reverse quantities not possible as Modvat is already posted. System Response The transaction cannot be processed. Procedure Reverse quantities option is possible for GR documents where Modvatposting has not yet been done. If the quantity to be reversed is equalto GR quantity, then select the option Reverse Document instead ofReverse Quantities.