Example of How to Change the Material Type 
Scenario
You want to produce a material that was only procured externally until now and whose material type is raw material. You now need to assign it to the material type semifinished product. In our example, no stocks exist yet for the material.
Procedure
The initial screen for changing the material type appears.
If you choose Enter, the system enters the old material type in the Old material type field.
A message appears telling you that you are changing the material type.

If, due to their valuation class, the two material types refer to different accounts, a dialog box appears asking you to enter a valuation class that is valid for the new material type for all plants or company codes. Confirm the new valuation class by choosing Enter.
Result
A message appears telling you that the material type has been changed.