ผมต้องการลบข้อมูล xml ออกบางส่วนผมจะทำได้ยังไงครับ

<?xml version="1.0" encoding="utf-8"?>
<messages>
    <message time="1248083538">
        <name>Ben</name>
        <email>Ben's Email</email>
        <msg>Bens message</msg>
    </message>
    <message time="1248083838">
        <name>John Smith</name>
        <email>[email protected]</email>
        <msg>Can you do this for me?</msg>
    </message>
</messages>

<?php

$doc = new DOMDocument; 
$doc->load('theFile.xml');

$thedocument = $doc->documentElement;

//this gives you a list of the messages
$list = $thedocument->getElementsByTagName('message');

//figure out which ones you want -- assign it to a variable (ie: $nodeToRemove )
$nodeToRemove = null;
foreach ($list as $domElement){
  $attrValue = $domElement->getAttribute('time');
  if ($attrValue == 'VALUEYOUCAREABOUT') {
    $nodeToRemove = $domElement; //will only remember last one- but this is just an example :)
  }
}

//Now remove it.
if ($nodeToRemove != null)
$thedocument->removeChild($nodeToRemove);

echo $doc->saveXML(); 
?>