At the Account Settings screen, tap the entry for Subscriptions. Here, you can view your active and expired subscriptions. Tap an active subscription you want to cancel, then tap Cancel Subscription (or Cancel Free Trial). Tap Confirm and you're done. A service you are already subscribed to will remain active until the end of that billing cycle.

If you're still on a free trial, the account may close right away. If you have a free or discounted trial subscription, make sure you cancel it at least 24 hours before the trial ends. Otherwise, the subscription may renew automatically before the cancellation is processed.

If you change your mind about a subscription before or after the expiration date, tap the subscription you want to bring back and select a payment option. If the app offers multiple subscription options, choose the one you want to pay. Confirm your changes and re-subscribe.

When you subscribe to an app, Apple generates a random Subscriber ID unique to you and the developer. If you cancel your subscription for an app and don't resubscribe within 180 days, your Subscriber ID is reset.

On a Mac, you can also go through the App Store to cancel and otherwise manage an app subscription. Open the App Store and click on your account name in the lower-left corner of the window.

At your Account window, click on the View Information link. Scroll to the bottom of the Account Information screen to the Manage section. Click on the Manage link next to Subscriptions.