Diagnosis
You want to update a reservation with a new material number. However,according to the FFF classlogic, it is not possible to use the specified material number.

System Response
The system rejects the new material number. An update is not possible.
For component installations and removals in transaction IE4N, changes toreservations only apply for interchangeable parts.

Procedure
Use a different reservation or component, or update the material numberof the reservation with one that is interchangeable with the originalmaterial number.