Renweal: Downgrade from Premium to Deluxe (10 licenses to 3 licenses)

You can do this by first logging into your Norton Account and clicking on the user icon at the top right. Then click on Manage my Subscriptions. Find your current subscription and be sure that the Automatic Renewal is turned off. Look to the right side of the subscription information. Then you can purchase the Deluxe version from a reputable retailer or directly from Norton. If you purchase directly from Norton, the new subscription will start at the time of purchase. A product from another retailer can be held until the expiry of your current subscription and entered into your product by clicking Help > Enter Product Key  from the classic interface.

One thing to remember is that if you enter a new product key before your existing subscription has expired, you will lose the remaining time and will have to contact Norton Support to have them add the time back to your new subscription. 

Or you could just contact Norton Support now and ask them to make the change to your subscription while doing the renewal for you.    www.norton.com/contactcs