Want to change my phone location from UK to US

See -> Change your Apple ID country or region

Change your Apple ID country or region - Apple Support (KW)

👉 What to do before you change your country or region

• Spend any balance remaining on your Apple ID. If you're not sure whether you have a balance, check your Apple Account balance.
• Cancel your subscriptions and wait until the end of the subscription period. 
• Wait for any memberships, pre-orders, movie rentals, or Season Passes to complete, and wait for any pending store credit refunds to process. You can cancel a pre-order.
• Make sure that you have a payment method for your new country or region. See what payment methods you can use.
• Redownload your apps, music, movies, TV shows, and books on any devices that you might use to play or read them in the future. Some types of content might not be available in your new country or region. Learn what types of content and services are available in your new country or region.

👉 If you can't change your country or region

• If you can't change your country or region, make sure that you canceled your subscriptions and spent your store credit. Complete these steps before you try to change your country or region.
• If you're a part of a Family Sharing group, you might not be able to change your country or region. Learn how to leave a Family Sharing group.
• If you still can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support.