I am afraid that there is no such transaction in standard to change the service category.
http://help.sap.com/saphelp_46c/helpdata/en/71/e12c7dd435d1118b3f0060b03ca329/content.htm
I am afraid that there is no such transaction in standard to change the service category.
http://help.sap.com/saphelp_46c/helpdata/en/71/e12c7dd435d1118b3f0060b03ca329/content.htm