About Restructuring Assembly Components
By restructuring assembly groupings, you can add flexibility to the assembly design process in the following ways:
Move components from one subassembly to another, from the top-level assembly to a subassembly, or vice versa. The top-level assembly must be in session to properly regenerate a restructured subassembly. Components with missing references are frozen.
Create a new, empty subassembly and restructure components to this subassembly, or select components and create a new subassembly. The first time you retrieve the subassembly without the top-level assembly, you must freeze all the components.
Create a drawing of the subassembly to list the components in a table for a BOM.
After you restructure a subassembly, you can add to it and modify it.