Use of word "& Co" and "Associates"

Dear Members,

I want to know whether the words like "& Co." or "& Associates"  after the name of the firm is to be used ONLY  by certified chartered accountant who is practicing in direct tax and indirect tax consultancy services and cannot be used by a person who is NOT a chartered accountant engaed in direct tax and indirect tax consultancy service.

Kindly discuss.

Thank you.