I am in a stuck case and need your help. I have already imported all customer contacts to Zoho CRM, all with "last name". I have many other csv files with new fields but without "last name" value. Now I want to import these csv files to update my existing database with new fields, however I dont want to map "last name" filed as they are blank in these files.

Please let me know what can I do to not lose all customer last name.

Thanks and best regards,

Minh