As Sean has mentioned you can use Part copy... Or you can use the "new" simplified assembly command. The result maybe a part if you save as a part!
A little help:
You could always export the assembly as step file or parasolid and during an import process tell the translator not to build an assembly structure.
You have to keep in mind that when you do this you put all the solid bodies into the assembly or part file. This is not a good practive but it does work.
Design Manager Streetscape Limited
Solid Edge ST10 [MP0] Classic [x2 seats]
Create a simplified version using all visable faces and save the simplified as a part