If you're using Master Model approach, the Drawings are in a separate part file from the Master Model and so all you have to do is delete the Drawing file and the Master Model will never no the difference.
If the Drawings are created inside the part models, then you can delete them by going to the Part Navigator and expanding the item labeld 'Drawing', select the sheet that you wish to delete, press MB3 and select the 'Delete' option.
As for creating Drawings of an Assembly, simple have the Assembly file open and have the Displayed Part also the Work Part and then create your Drawing.
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA Siemens PLM: UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.