If you want to cancel your Amazon Prime Video subscription, then you can do it any time from the memberships and subscriptions in your account. To process for cancellation of a subscription, you will have to do the following steps,
After login into your account, go to ‘Your Memberships and Subscriptions.’
Now select ‘Manage Subscription.’
You have to click the link under advance Controls so that you could be directed to the main subscription page.
From the main subscription page, you can end your subscription.