Hi,
I added a search, it is by email only.

after the line:
Code:
$action = (isset($_GET['action']) ? $_GET['action'] : '');
add:
Code:
$searchemail = (isset($_POST['email']) ? $_POST['email'] : '');

after the line (around line 80) :
Code:
<td class="pageHeading"><?php echo PASSCHANGE_HEADING_TITLE; ?></td>
add:
Code:
<td class="pageHeading">Search email <form action='' method=post><input type=text name=email><input type=submit></form></td>
Around line 98 :
Code:
    $passchange_query_raw = "select customers_id, customers_lastname, customers_firstname, customers_email_address from $passchangeCust order by customers_id";
replace with:

Code:
  if ($searchemail){
		$passchange_query_raw = "select customers_id, customers_lastname, customers_firstname, customers_email_address from $passchangeCust WHERE customers_email_address='$searchemail'";
  }else{
		$passchange_query_raw = "select customers_id, customers_lastname, customers_firstname, customers_email_address from $passchangeCust order by customers_id";
  }
It is quick and dirty, does not take into account languages etc but works for me.

Enjoy: