cannot remove email account for superadmin under Change Login Email IDs via Users Detail

cannot remove email account for superadmin under Change Login Email IDs via Users Detail

cannot remove email account for superadmin under Change Login Email IDs  via Users Detail in the email dashboard

https://mail.zoho.com/cpanel/index.do#userdetails

I accidentally ended up with an organization email tied to this account that was supposed to go to a regular user ,. It is not primary on the superadmin account . It will not however let me change or delete it . 

zoho userid :   41375597 , doug.twyman
email acct in question :  mike@vickis-kitchen.com   

cannot seem to unattach it from the doug.twyman account

thank doug -ft