Subscription: How to change the quantities of specific orders or skip weeks
Go to your account page (little person blob on the top right of each screen) and then "Manage Subscription".
Click on this and then the dropdown under "Manage" gives you lots of lovely options, including amending address credit card details, and, importantly your next seven "Upcoming Orders".
Under "Upcoming Orders" you can amend quantities in any given order or skip weeks if you happen to be going on vacation. Changes can be made any time until the midnight Friday deadline, which is when your credit card will be charged.