First you need to log out of your local App Store:
Launch App Store from your Home screen.
Tap on Apple ID: [your current email] at the very bottom.
Tap on Sign Out.
Next you need to change the region on your iPhone or iPad:
Launch Settings from your Home screen.
Tap on General.
Tap on Language & Region near the bottom.
Tap on Region
Check off United States.
Now you need to create the new account in the store of that country:
Go to the app listing on the App Store on your iPhone or iPad.
(Tap Change Store if it stays stuck on your old region and says the item isn't available in the current store.)
Tap Get.
Tap Install.
Tap Create New Apple ID
Check the country if it isn't already checked.
Fill out the required information.
Tap None for billing information unless the app isn't free.
Launch Mail to verify the email address you used for the new account.
Finally, download the app:
Go to the app listing on the App Store on your iPhone or iPad.
Tap Get.
Tap Install.
Login to your new iTunes Account if you aren't already logged in.
Repeat the Get and Install steps if you have to.
That should start your app download
Cheers