Here are the steps:
1) Log in to the WintellectNOW site.
2) Click your name in the upper-right corner of the page, and then select "My Profile."
3) Click the account that you wish to disable auto-renewal for under "You are an administrator for the following accounts."
4) Click the "Disable Auto-Renewal" button under "Subscription Information."
5) Click the "Disable Auto-Renewal" button in the ensuing dialog.
You will continue to enjoy access to WintellectNOW until your subscription expires, but the subscription will not auto-renew.