Change my country/region

What country are you trying to change too? The one you are trying to change to may not be available. See Change your Apple ID country or region https://support.apple.com/en-us/HT201389. Be sure and use the support options below if you have a problem. And see this part of the contents of the document: Learn what types of content and services are available in your new country or region. You can use this link to see if your country is available.

What happens when you try? Error message(s)?

You need a zero account balance and you need to cancel all your subscriptions. If you have cancelled all subscriptions, but some haven’t expired, contact iTunes Support. You need a valid credit card issued by a bank in the country the store is in and you need a billing address in that country. If you have an account balance, either buy something more expensive and pay the balance with a credit card or contact iTunes Support and ask them to zero balance your account.

Purchases - View, change, or cancel your subscriptions.        

Purchases - Subscriptions not billed through Apple     

Region - Change your iTunes Store, iBooks Store, or App Store country or region.     

If necessary, contact iTunes Support. Follow through the screens to get a chat or telephone option.  

iTunes Support – world wide   

Apple Support schedule phone call