You can deactivate the automatic renewal of your subscription at any time in your account settings.
To cancel your subscription, open the Settings app on your iOS device. Tap on your name and then tap iTunes & App Store. Now tap your Apple ID and then tap Show Apple ID. 
Now tap Subscriptions. Here you can manage or cancel all your subscriptions, including your Lords & Knights passes. 

The following graphics will lead you through all the mentioned steps: