The edit profile button is located below the name of the user.
The Edit Profile Button allows the user to edit their Password, Profile picture, and their Signature. Note that in order to use the signature that the user typed in, they must check the "Use personalized signature instead of system default signature" button.
As seen in the display above, in order to change a password, a user simply confirms that the User name listed belongs to them, and then enters and re-types the new password. Once those fields have been entered, the user clicks on Save & Close to change the password. At any time throughout the process, the user can click on the Cancel button to go discard their changes and go back to the Home screen.