in the UE code, there will be a line to set a variable named $EmailRef, for example:
$EmailRef = "waue_pagename_1";
this is used as a session name further down to store the email status:
$_SESSION[$EmailRef."_Status"] = $GLOBALS[$EmailRef."_Status"];
if the email is successful, that session will equal "Success", you could hand code an if statement around the update code:
<?php
if(isset($_SESSION['waue_pagename_1_Status']) && $_SESSION['waue_pagename_1_Status'] == "Success") {
<perform update>
}
?>