If you'd like to unpublish a memorial website that you've created, login to your account and make sure you're on your dashboard page. From there, click 'Edit memorial' for the memorial website that you'd like to unpublish.
Scroll to the bottom of the page, and you'll find a link that says 'Unpublish memorial website'. Click that link and then click the teal button on the next page to confirm that you'd like to unpublish it.
Once a memorial website has been unpublished, it will no longer be viewable publicly on the internet, but you'll still be able to view it when you're logged into your account.
If you change your mind at a future date, you can always republish the memorial website from your dashboard.