ldap_exop_passwd

<?php
$ds = ldap_connect("localhost");  // assuming the LDAP server is on this host

if ($ds) {
    // bind with appropriate dn to give update access
    $bind = ldap_bind($ds, "cn=root, o=My Company, c=US", "secret");
    if (!$bind) {
      echo "Unable to bind to LDAP server";
      exit;
    }

    // use PASSWD EXOP to change the user password for a generated one
    $genpw = ldap_exop_passwd($ds, "cn=root, o=My Company, c=US", "secret");
    if ($genpw) {
      // use the generated password to bind
      $bind = ldap_bind($ds, "cn=root, o=My Company, c=US", $genpw);
    }

    // set the password back to "secret"
    ldap_exop_passwd($ds, "cn=root, o=My Company, c=US", $genpw, "secret");

    ldap_close($ds);
} else {
    echo "Unable to connect to LDAP server";
}
?>