Real Money Account
Once you create an account, its base currency cannot be changed. Your portfolio, orders, results, transactions are all displayed in the currency which you've selected.
An alternative would be to close your existing account with us and open a new one in the preferred currency, as long as it is supported on the platform.
NOTE: If you decide to close your account now, you can check whether registrations are open for your region.
Practice Account
To change the currency of the account is needed to reset it from the Settings Menu 
→ [Reset account].