Thank you for using Apple Support Communities! I understand that you would like to change the country for your Apple Music subscription. I would be happy to help provide clarification about this process.
Before changing your country, you'll need to cancel any subscriptions, including Apple Music. Once you have reached the end of the subscription period, you can then change your country and start a new Apple Music subscription for that country. Keep in mind that you would not be able to transfer the content currently in your iCloud Music Library from one country to another.
The following resource provides more information about what to do before changing your Apple ID country or region: