To upgrade your existing CBS All Access subscription from Limited Commercials to Commercial Free via your iPhone or iPad, please do the following:
1. On your iPhone or iPad homescreen, tap Settings > iTunes & App Store.
2. Tap Apple ID > View Apple ID, and enter your Apple ID password or use Touch ID to sign in.
3. Scroll down. Under "Subscriptions", tap "Manage". You will see all of your active subscriptions.
4. Select your CBS All Access subscription, and Upgrade.
If you don't see your CBS All Access subscription but are still being charged, make sure that you're signed in with the correct Apple ID. If you are, then you might have subscribed on another device, or through CBS.com, and not through iTunes. Please return to that device or CBS.com to upgrade your subscription. Instructions on how to upgrade your subscription on other devices can be found here
For more information, please visit www.cbs.com/appletv/upgrade