Go to your Profile page:
Select the Edit button at the top right-hand corner of the page.
Click the "Edit" button next to Contacts.
The key icon to the right of the email address is the primary address for embedADAPT and one which cannot be deleted.
Overwrite the existing email with the new email address and click Save & Close.
To update the email of another employee you can do this via their Profile page (accessed via the Manage People) but you will need TSL access in order to do this.
Setting up a personal profile