There is no direct way to change the login email address. But you can do the following
Invite a new member to your team using the new email address.
Confirm the invitation and login with the new email.
Delete the team member with the old address.
If you want to change the email addresses for notifications (alerts/warnings) go to Recipients. Every new team member is added as a recipient for notifications automatically.
But review the settings carefully so they fit your needs. Deleted team members are not removed from the recipients' list. You must do this manually.