To update the details of your subscriptions and their renewals, follow these steps:
1. Open the App Store application.
2. Scroll to the bottom of the Featured page and click on your Apple ID (or Sign In).
3. A new window will pop up - tap View Apple ID.
4. Under Subscriptions, click Manage. If you don't have any subscriptions this button will not be displayed.
5. From here, tap the app subscription that you would like to manage and you will see the current subscription status and available options. If you only subscribe to one publication, you will see the current subscription status and options without needing to select a subscription.
6. Tap the desired renewal option to select it.
7. You will see a confirmation window asking you to confirm your purchase.
8. Tap OK to proceed with your purchase.