1. Open the Settings app.
2. Select the top entry, which is your name, followed by Apple ID, iCloud, iTunes and App Store.
3. Tap iTunes & App Store.
4. Tap Apple ID: yourname@email.com
5. Tap View Apple ID.
6. Tap Subscriptions.
7. Scroll to and tap on RoboKiller - Block Spam Calls.
8. Tap RoboKiller Yearly Membership.

1. Open iTunes on your Mac or PC.
2. In the Account menu select View My Account…
3. In the Settings section, select Manage next to Subscriptions.
4. Select RoboKiller - Block Spam Calls from the list of apps.
5. Choose RoboKiller Yearly Membership (1 Year).
6. Select Done.

Unfortunately, this process is not possible for the Google Play Store and Android devices. If you have an Android device and would like to upgrade from monthly to yearly, you will need to cancel your current subscription and sign up with a new plan.