Welcome to TinyDeal.
If the order is still not shipped, please tell us the model you would like to exchange and we will help you finish it in our system. By the way, the exchange result will be only shown in our system, but not in your ordering manager. If you want to cancel the order, we will also can help you cancel and then refund (money or TD points).
But if your order has been shipped out already, we are afraid that no change or cancel can be done. Hope your understanding.
Any questions please contact us by Customer Service Express: http://help.tinydeal.com/contact-us