Zend certified PHP/Magento developer

Reorder checkout shipping address form fields

I would like to reorder the checkout form fields in following order

  1. First Name

  2. Last Name

  3. Email

  4. Phone number

  5. Custom field – opt-in

and then the rest of the fields.

I can reorder other fields in checkout_index_index.xml however, email is not the customer address form field.

How can I achieve the mentioned order of the form fields?