function unregister_globals() {

    if (ini_get('register_globals') == 0) {
       return;
    }

// Save the existing superglobals first
    $REQUEST = $_REQUEST;
    $GET = $_GET;
    $POST = $_POST;
    $COOKIE = $_COOKIE;

    if (isset($_SESSION)) {
        $SESSION = $_SESSION;
    }

    $FILES = $_FILES;
    $ENV = $_ENV;
    $SERVER = $_SERVER;

// Unset the $GLOBALS array (clear all)
    foreach($GLOBALS as $key => $value) {
        if ($key != 'GLOBALS') {
            unset($GLOBALS[$key]);
        }
    }

// Re-assign the saved superglobals again
    $_REQUEST = $REQUEST;
    $_GET = $GET;
    $_POST = $POST;
    $_COOKIE = $COOKIE;

    if (isset($SESSION)) {
        $_SESSION = $SESSION;
    }

    $_FILES = $FILES;
    $_ENV = $ENV;
    $_SERVER = $SERVER;
}

Emulate Register Globals being Off when you can't (or don't want to) change php.ini for your entire site

Unregister Globals Function

PHP