Negation logic in SAP ABAP

You can use BOOLC to sort out your requirement. It should be like this

Varbool= BOOLC( NOT Logical operation)

But be clear in your implementation, as ABAP does not have true bool type. It does not store true or false in bool type rather it stores ‘X’ or ‘’ for true and false respectively.

You can also try to use XSDBOOL instead of BOOLC.