Will I be charged cancellation fee If I change plan?

You shouldn't if you  go to Adobe Customer Service (Make sure to sign in to your Adobe account first and allow popups and cookies on your browser. You may not be able to see the chat window if using a VPN.):
https://helpx.adobe.com/contact.html?rghtup=autoOpen will automatically open the chat window.
Type "Agent" in the chat box to bypass the chatbot and be connected to a person.

or X (was Twitter):
https://twitter.com/AdobeCare

Hey there, this is a user-to-user forum. You'll have to contact Adobe Support directly to see what they say. Hopefully if you want to change plans you won't be charged a fee, but only a support rep could give you an actual answer.