To export parts of the drawing or specific entities you can use the EXPORTDRAWING command.
To write entities, a Block, or the drawing to a new drawing file:
Type -ExportDrawing at the command prompt.
Specify the name of the new drawing (including the path).
Specify an option:
Entities. Press Enter to run the default option to write specified entities to file: In the graphics area, specify the insertion base point. Specify entities and press Enter. The specified entities are deleted. Use the Undelete command to restore them.
Specify block name. Type the name of an existing Block in the drawing to write to file.
* For entire drawing. Type an asterisk to save the drawing.