Are we talking about just 'renaming' the Component object itself, as found in that particular Assembly, and NOT actually renaming the Master Part file that the Component was created from?
If so, simply select the Component of interest, either from the screen or the Assembly Navigator, press MB3 and select the 'Properties' option. Then select the 'General' tab and there you will find a field to replace the default 'Name' of the Component with whatever you wish.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Digital Factory
Cypress, CA Siemens PLM: UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.