Relevant article: Managing Roles and Access Permissioning
It's common to have a new profile with another email, and in that case, you can follow these steps:
Log in with current credential, and go to Agency Settings
Invite a new team member with the desired email (as Manager role)
An invite will be sent to the new email address, and will need to be accepted
Going forward, you can just log in with the new email.
We wouldn't recommend to change current email addresses for logins as it can result in potential issue down the line.
Hope it helps, and feel free to let us know if there are any questions via email to (firstname.lastname@example.org) and/or via pop-up chat on the page's bottom.