The following steps will guide you on cancelling a limit order sell:
Go to wallets,
Select the asset you wish to cancel the sell order set,
Swipe to Open Orders,
Click on the Order set,
Click Cancel Order.

The following steps will guide you on cancelling a limit order sell:
Go to wallets,
Select the asset you wish to cancel the sell order set,
Swipe to Open Orders,
Click on the Order set,
Click Cancel Order.