def METHOD_NAME(change_request) -> None:
    """Change the user's email address if the request was completed and send the completion email.
    :param change_request: the email change request
    """
    if not change_request.completed:
        return
    member = change_request.member
    member.email = change_request.email
    member.save()
    emails.send_email_change_completion_message(change_request)