Administrators can change other users' email addresses. When an email address is changed, the assigned username is automatically updated, since it must always match the email address on file.
In the administration area, you’ll find the Users tile. There, you’ll see an overview of all users set up in your organization’s account. Select the person whose information you want to change. To do so, click on the person’s name. You’ll now see their profile. In the Email Address field, click the Change Email Address link. Enter the new email address, update your password, and then click Send Confirmation.
The person in question will automatically receive an email notifying them of the change. This email will be sent to the new address. The person can confirm their new email address by clicking a link in the email.