<?php
$con = mysql_connect("localhost","root","root");
if (!$con)
  {
  die('Could not connect: ' . mysql_error());
  }
 
 
mysql_select_db("onm", $con);
 
 
$result = mysql_query("SELECT * FROM lease_center WHERE (current_date() >= (LAPeriodEnd - INTERVAL 90 DAY)) AND (current_date() <= (LAPeriodEnd - INTERVAL 0 DAY)) ");
while($row = mysql_fetch_array($result))
  {
  echo "<table cellpadding=2 cellspacing=2 width=100%>
<tr>
 
 
</tr>";
  echo "<tr>";
  echo "<th bgcolor=#FFCC00  width=250px>SiteId</th>";
  echo "<td bgcolor=#FEE9A9>" . $row['SiteId'] . "</td>";
    echo "</tr>";
  echo "<tr>";
 
 
 
 
	echo "<tr>";
  echo "<th bgcolor=#FFCC00>
  LAPeriodEnd</th>";
  echo "<td bgcolor=#FEE9A9>" .date("j-F-Y",strtotime($row['LAPeriodEnd'])). "</td>";
    echo "</tr>";
 
	echo "<tr >";
  echo "<th bgcolor=#FF6600 height=10px>
</th>";
  echo "<td bgcolor=#FF6600 height=10px></td>";
    echo "</tr>";
 
 
 
  }
echo "</table>";
 
 
mysql_close($con);
 
 
 
?>

find users query
 
while (all users)
{
	htmlmessage=""
 
	while ( find all expired records for current user (as you are doing in your code for logged user only))
	{
 
		   create htmlmessage string intead of echoing output directly to browser.
	}
	mail('usermaiid',htmlmessage);
 
 
}

 
	find users query
 
	while (all users)
	{
		htmlmessage=""
 
		while ( find all expired records where mail is not sent for current user (as you are doing in your code for logged user only))
		{
 
		   create htmlmessage string intead of echoing output directly to browser.
		   set mail sent flag for current user and current record to yes (mysql update)
		}
                if(htmlmessage!="")
			mail('usermaiid',htmlmessage);
 
 
	}