Here are the steps for applying a Thrivous reward discount code to an existing product subscription:
1) At the Thrivous website, login to your Thrivous account. You should see the Account webpage, as well as an "Earn Rewards" button (bottom of screen on mobile, and bottom right of screen on desktop).
2) Select the "Earn Rewards" button. You should see a popup menu that displays your Thrivous rewards balance, along with a "Spend Points" option.
3) In the popup menu, select "Spend Points." You should see a list of reward options, including options for "$X off subscription code."
4) Select one of the "$X off subscription code" options and follow instructions to get the discount code.
5) Back on the Account webpage, select "Manage Subscriptions." You should see a list of your Thrivous product subscriptions.
6) On the Subscriptions webpage, find the product subscription to which you'd like to apply the discount, and select "Apply Discount Code." You should see a text field appear for inputting the discount code you received in step #4.
7) Apply the discount code. The value of the discount will be deducted the next time your subscription renews.