Maybe try:
@session_start();
session_regenerate_id(true);
session_destroy();
session_commit();
session_start();
If that doesn't work, then you could try also adding:
if (ini_get("session.use_cookies")) {
$params = session_get_cookie_params();
setcookie(session_name(), '', time() - 42000,
$params["path"], $params["domain"],
$params["secure"], $params["httponly"]
);
}