To exchange money and cryptocurrencies automatically you can use Limit or Stop Orders.
A Stop Order is an order to buy or sell once the price of the asset reaches a specified price, known as the stop price. When the Stop Price is reached, a Stop Order becomes a Market Order and is executed at the best available price (which can be lower or higher than the Stop Price).
A Limit Order is an Order to buy or sell at a specified price or better. Buy Limit Orders will be executed at the specified price or lower, Sell Limit Orders will be executed at the specified price or higher.
The feature to exchange money automatically was previously called Auto-Exchange.
To cancel a currency order, please access the Orders list. There, you can either swipe on a pending order to access the delete action or alternatively tap on it: the order summary screen will open and you will get access to a delete button.