Orders can be changed or canceled from the:
You can cancel one order as described above or you can cancel all open orders.
For open Smart orders, you may be able to make changes to the order, such as quantity, type, limit price and more. Click the order you wish to change and click Change Order at the top of the window.
A window with the order entry fields will open with your original order settings. Make the desired changes and click Review Order (or Cancel Changes if you want to keep the original settings). If the settings are correct upon review, click Place Order.
Note that you cannot change a Smart order to or from a trailing stop order type after the order has been submitted. You must first cancel the order and then resubmit with a different order type.
Orders with Brackets: You can change the primary order using Change Order as described above, but to change the bracket exits themselves, right-click on the contingent bracket in the Order Status tab and select Edit Bracket. You cannot change the order AND its associated brackets via the Change Order function.
NOTE: Some orders, including all Direct Access orders and market orders (unless trading on the security has been halted), cannot be changed. Further, because of the speed of execution and the short life span of marketable limit orders, canceling or changing orders may not always be possible.
Refer to the Change column in your Order Status tab to see if an order can be changed, indicated by a Yes
You can change and cancel orders from the Order Status Indicator found at the top of either the Trade tool or Symbol Hub or in the Option Chains. Click on the indicator to view your choices for your open orders in the selected position.
Read more about the Order Status and Position Indicators.