Changing Material Type

Hi,

There are some materials (~100Nos) which require material type to be changed from Semi-finished to finished.

Some have Production orders & the valuation stock also exists.

I have got information from SAP HELP the prequisites still I have a clarification on Account category reference.

The Account caterogy reference is different for the Old & new material type.

Can it also be changed & what are the pre-cautions be be taken?

Any other views please on changing material type?

Regards,

Vengat