Changes the name, domain or custom field values of the customer account with the given external ID. Only the fields you send change; custom fields you leave out keep their values. The request is all-or-nothing: if a custom field is rejected (422), none of the changes are saved, including name and domain. The external ID itself cannot be changed. External IDs in the path may contain dots (for example refine.com). Do not add a format suffix such as .json to the path: it would be read as part of the ID. Requires the customer_accounts_update permission.