In my database - contact list, I have 2 columns: First name and Last name.

Some of my contacts have a blank in First name while their actually first name are inputting in Last name.

Therefore, I try to copy all their Last name, move to First name, which is now Last name will be blank.

* There is a problem: After leaving a blank in Last name and import list, Zoho still keep the old Last name field, which turn my contact into, ex: First name: John - Last name: John.

How can Zoho knows I want to turn a field into blank after updating?

Thanks,