If you need to cancel an order before the confirmation cut off (12:00 pm on the displayed order processing date) you simply need to:
Step 1: Head to the 'Transactions' tab at the top of your dashboard.
Step 2: Locate the pending order you would like to cancel then click on it to open a drawer on the right side of your screen.
Step 3: Select 'Cancel transaction' near the bottom of your screen.
Step 4: If you're sure you want to cancel, click 'Cancel transaction'.
Step 5: Refresh your browser and your pending order should no longer show in your transactions.