Changing an Email Address
The email address associated with your Trello account, also referred to as an account credential, can be used to log in to Trello, recover an account when the password has been forgotten, receive Trello notifications, or as a way for other Trello members to be able to add you to their boards for collaborating on a project. You may have one email address per account and you will use this single email address to log into Trello and recover your account if your password has been forgotten.
Changing an email address
To change the email address you use to log into Trello, go to your account settings page at http://trello.com/my/profile and click on Profile & Visibility. Then select Change email address from the Contact section.
A confirmation email will be sent to the new email address. After clicking the link in the email to confirm the change, you’ll need to log in again with your previous email address. Then, you’ll see your Profile & Visibility page is now updated with the new email address and your previous email address is removed from the account..
If you currently have more than one email addresses on your account, you must remove your additional email addresses in order to change to a new email address.
Please note: It is not possible to change an email credential to an email address that is already in use with another Trello account.
For information on merging Trello accounts please see this article.