I have another person on my TT Account who shares my email. He needs to change from my email to his new email address. How is that done?

[DoninGA]

The TurboTax online editions are only for one tax return per account and User ID. 

If this other person has their own TurboTax online account with a separate User ID then they can change any of their information on their account.

See this TurboTax support FAQ for updating a TurboTax account - https://ttlc.intuit.com/community/account-updates/help/how-do-i-update-my-turbotax-account-informati...