If you move to a new country, you can change the country of your existing iTunes Store account (Apple ID) on your iPhone, iPad, iPod touch or Mac or PC. If you don't change your country when you move, it's possible that your credit card won't be accepted for payment. For example, only German credit cards can be used to buy content from the German iTunes and App stores.
After you change the country of your account, you won't see the items you purchased from the previous country’s store in the Purchased section.