BOM Information Needed Please

Hello again,  I am putting together a BOM on an assembly drawing for the first time.  Some of the parts just have a description and no part number.  The BOM automatically puts my file name in for the part #.  Is there a way just to leave that part blank?  Also I would like to change some of the part numbers to match our new numbering system.  Should I go change the file names or can I just change it here in the BOM and it will accept that?  Thank you.

SolidworksAssemblies