Diagnosis
You are trying to delete an entry from a document. There is only oneentry left in this document. Every document must have at least oneentry.

System Response
The system will not delete the entry.

Procedure
If you want to define a retirement for the document, set the retirementamount for AC/PC and input tax to 0.0. The document must remain in theoverview, but it can be defined without a retirement amount.