Change pounds to us dollar

See the support options given here:

If you have a credit balance (e.g., a cents credit balance), you could purchase something of value greater than or equal to the amount of your store credit or try to get Apple Support to zero out your account balance using this support link https://getsupport.apple.com/?caller=cups&PGF=PGF63006&category_id=SC0060&symptom_id=23330 This link is derived from Change your Apple ID country or region (see below). It also applies equally well to debit balances.

Since you are interested in Changing your Apple ID country or region, see https://support.apple.com/en-us/HT201389. Be sure and use the support options below if you have a problem. See this heading especially What to do before you change your country or region.

·      Spend any store credit remaining on your Apple ID. Learn what to do if your remaining store credit is less than the cost of a single item.

·      Cancel any subscriptions, including Apple Music, 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.

·      Make sure that you have a payment method for your new country or region.

·      Redownload your apps, music, movies, TV shows, and books on any devices that you might use to play or read them in the future. That's because 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.)

Use this link in the document if you need to View your Apple ID balance https://support.apple.com/en-us/HT202359

If you can't complete any of the steps, can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support.

And you also can contact iTunes worldwide support to get help via text, chat, or phone using this link https://support.apple.com/choose-country-region/itunes. At the bottom of your screen, use Tell us how we can help to select among support options.

Do you have a support question?

1. Open the Settings app. 
2. Tap your name, then tap iTunes & App Store.
3. Tap your Apple ID, then tap View Apple ID. You might be asked to sign in.
4. Tap Country/Region.

What country/region shows there?

What shows if you tap the Account balance at the top right?