3645196 - Error when updating an already sent/ordered Purchase Order Item.

You are using an external application to update the UoM (Unit of Measure) or the ordered quantity of an already Sent/Ordered Purchase Order item.

This error message shows up from the external application:

"Changing UoM not possible; field is read-only. ERROR: Changing Ordered Value not possible; field is read-only."

SAP Business ByDesign

Maintain the data from the external application in order to update your Purchase Order item.

The error message pops up.

This is the expected system behavior. 

Either directly from Business ByDesign of from a 3rd party application, it is not permitted to modify the Unit of Measure or the ordered value of a Purchase Order Item.

Purchase Order Item; 3rd party application; Changing UoM not possible; field is read-only; ERROR: Changing Ordered Value not possible; field is read-only. , KBA , SRD-SRM-PRO , Purchase Requests and Orders , Problem