SAP Message UCM0088 - Inversion document &2 from &3 / &4 belongs to document &1

Diagnosis
Document &V1& has been already inverted by document &V2& in period &V3&/ fiscal year &V4&. Further processing of these two documents willcommence only in pairs. Document &V2& is not being displayed because itdoes not lie within the timeframe you selected.

System Response
If you reverse document &V1&, then document &V2& is also reversed.