Only the month-to-month plan can be paused, yearly plans (billed monthly or paid upfront) cannot be paused.
After logging into your Slate Digital customer portal, click on Account Info. There will be a pause button under your membership. After having confirmed, your membership will be paused.
Your account will not be charged until you resume your membership, but the current billing is due: no proration (no refund) is performed, and your licences remain active (and so, you can use your plugins) until the end of the current billing cycle. After that date, your licences will expire and you will not be able to use your plugins anymore.
You can resume your membership by clicking on resume at the bottom of the membership. After having confirmed, your membership will resume. If you resume during the same billing cycle you paused, you will be charged at the same date as before. If not, billing will now happen every month at the date you resumed.