Risks about changing region

Hi,

Since I moved in Singapore I need to download some apps on my iPhone only available on the Singaporean's App Store. From what I understood I have to change the region of my account from my current country to Singapore.

But I can't find a satisfying answer about what will happen to the content I own in the current country. What happens to the movies/tv show I already have ? What will happen to the app ?

I still have a credit card in both the countries and I plan to keep them, is it possible to access 2 apple stores with 2 credit cards with a single Apple ID ?

Thanks in advance,

Mathieu