1)As I given to understand cover order can be modified and cancelled until the given position(buy/long or sell/short) is not executed and pending. 2)once the order executed only the stoploss can be modified and order cannot be cancelled. 3)Suppose the cover order placed is executed and not reached the target yet,but you need to come out of market or stop trading ,in that case you can square off the position at current market value at that time (market value). 4)Once you've placed an order, you may have the option to cancel it before it's executed. You can only cancel pending orders. You can't reverse an order that's been executed in the market. There are two ways to cancel a pending limit order or stop order in your app.