How to change a subscription course?

For example, if you are subscribed to "Jorte Plus" and want to change to "Jorte Premium", you will first have to cancel "Jorte Plus".
After the contract period of "Jorte Plus" expires, you will be required to subscribe to "Jorte Premium".

You cannot "change from annual to monthly" or "change from monthly to annual" during the Jorte Premium contract.
If you want to change, cancel the current Jorte Premium contract, and after the contract period ends, you will be asked to subscribe for another period.