You can cancel your order before the start of the next trading window following the steps below:
Portfolio -> 'Orders placed' -> 'Cancel'
Trading windows are 2:00 pm and 7:00 pm on business days. If you submitted your order after 7 pm, you can cancel it until 2:00 pm the following day. If you submitted an order in the morning you can cancel it until 2:00 pm the same day. Orders can be cancelled at any point during the weekend and bank holidays. Orders cannot be cancelled during the trading window.
Once we’ve cancelled your order, you can submit a new order. We’ll endeavour to cancel your order in time for you to place your new order by 2.00 pm for the same day’s trading window.