SAP Message WW607 - Inventory management defined for & (&)

Diagnosis
Value-based inventory management is planned at this level. A change inthe hierarchy would have far-reaching consequences, not only ininventory management (in the Information System, for example).

System Response
This object cannot be reclassified.

Procedure
You have to decide whether or not you wish to/are able to change theinventory management levels for this object. You may have to carry outinventory revaluations "manually".