If you've started playing in the training ground for one country, but now you'd like a change of scenery, it's easy to switch countries. (No passport required.)
Note: Updating your country will only trigger a change in the countries attacking you
Go to Training on the top menu then click Mission Control
Note: If you wish to train on a different language, please navigate to Training--> Languages
Select the desired level of vulnerability and you will land back in the training ground
From here, click the home icon to change your country
Select your new country and click update
All done! Now you can start defending your new country.