SAP Message R1791 - You May Only Change Validity Dates

Diagnosis
When you are carrying out relationship maintenance not in dialog mode,you should change other data besides validity data.
If you use the classical Business Data Toolset (BDT), only changes tovalidity data are permitted.

System Response
The change is not made.

Procedure
Contact SAP. The program might need adjusting to incorporate the BDT inthe subscreen.