For whatever reason why you want to cancel an order, all you would do is click the trash can from the main menu.

Cancel an order.

This will bring the list of current order that are pending. Now select which order you want to cancel. now that order has been successfully cancelled.

• Sign up for an account and login.
  Sign-up for a Mock Trading Account

• Once you picked out a trade based on the formations, strategy, or guess, you will open an order.
  Place an Order

• If you would like to place a stop order or exit your contract(s), you would exit your order.
  Exit an Order