Change ZohoadminuserID

Hi,
When i started with ZC, i used my personal email as my zohoadmin user ID
Now, i have a zohomail id, which i want to use as the zohoadminuser id

The reason i woud like to change is when i use the
send mail - fature, ... my personal email is used..
I woud like to use my zoho mail for all correspondences genreted via zoho forms.

Please help me on how to do this
Thank u
Regards
Deepa