You can easily change your subscription plan through your iPhone or iPad settings. Follow these steps:
Step 1: Open your subscription settings
Open the Settings app on your device.
Tap your name at the top.
Select Subscriptions.
If you don’t see Subscriptions, select iTunes & App Store → tap your Apple ID → choose View Apple ID and sign in → scroll down and tap Subscriptions.
Step 2: Select your app subscription
Find and tap our app subscription.
Press the See All Plans button.
Step 3: Choose a new plan
You’ll be directed to a list of available subscription plans.
Select the plan that best suits your needs.
Your subscription will update immediately according to the new plan.