There is no way to change the Region on console.
It all depends on your PSN accounts region afaik.
So, as a workaround: Create an Asian PSN Account and to avoid buying the game a second time, make your US account a primary account on the console.
… But still: You will have a blank online character rooster this way, so … maybe you will have to bind your new Asian PSN Account to your current battle.net account … I don`t know. you should find appropriate Information with the use of Google and such.
Also normally, creating an PSN account witch is not in the same country where you live, is against Sonys ToS. So do not expect official support from any party.