delete secondary email

delete secondary email

Hi. I used lienhe@pnvcargo.com.vn as my first email when I set up zoho service. Unfortunately I can't find a way remove this address from my administrator account and assign this address to a normal user.
I've added another email @pnvcargo.com.vn to my account and make it primary email address.
Please help me remove lienhe@pnvcargo.com.vn 
Thanks!