Log in to your LeadOwl account from the desktop/web app version.
Click on Your Account Name from the far top right.
Click On Account 

From the Account page, click the Manage Subscription button.
Click your Current Subscription

Click Cancel Subscription

After clicking the Cancel Account button, your account is now canceled.  You will continue to have access through your bill date to your LeadOwl account and your clients and sales reps (if applicable).

Your subscription will cancel, and you will not be rebilled unless you choose to reactivate your account.