You can remove the assembly relationship between individual elements in a selected assembly at any time using the following procedure.
- In the drawing area, select the assembly.
- Click Modify | Assemblies tab
Assembly panel 
(Disassemble).
The disassembled elements remain in the model. Other instances of the same assembly type are unaffected. If the assembly you disassemble is the last or only one of its type, then that type and any of its associated assembly views are removed from the project.