Found the answer on the forum
Working code for destroying session and regenerating user session...
Just check to see if the session of your users also is UserID or named differently...
<!-- CLEAR CART SESSIONS -->
<?php
// Initialize the session.
// If you are using session_name("something"), don't forget it now!
@session_start();
//store the user session
$userSession = $_SESSION['UserID'];
// Unset all of the session variables.
$_SESSION = array();
// If it's desired to kill the session, also delete the session cookie.
// Note: This will destroy the session, and not just the session data!
if (ini_get("session.use_cookies")) {
$params = session_get_cookie_params();
@setcookie(session_name(), '', time() - 42000,
$params["path"], $params["domain"],
$params["secure"], $params["httponly"]
);
}
// Finally, destroy the session.
session_destroy();
unset($_SESSION);
session_start();
session_regenerate_id();
//reset user session
$_SESSION['UserID'] = $userSession;
?>