How do I remove the personal email address?

How do I remove the personal email address?

I set up a free personal zoho.com email address by mistake before going to business email and adding the correct email addresses for my domain.

However the personal @zoho.com email address is still there, sitting as a primary email address for me as a user in my mail account.

I had to add my business emails as alias addresses and make one of them a default to stop my replies appearing as "on behalf of xxx@zoho.com"

How do I remove this personal zoho.com email account as I have not used it and will never use it?

If I add my own personal email accounts later they will not be this address, so it is unnecessary.