Please visit the following Apple website.https://support.apple.com/en-gb/HT202039
To launch ChemGraphic, you need an internet connection for authentication and your credit card information registered in the App Store app. For information on how to register your credit card information, see the Apple Inc. website below.https://support.apple.com/HT201266
For example, if you switch from a weekly subscription to a monthly subscription during a subscription, it will automatically switch to a monthly subscription after the weekly subscription period ends.
If the process ends immediately due to cancellation, the point of cancellation will be the switching timing.
It is the same for each subscription plan such as weekly and monthly. Please note that each is not a separate item.