Update custom order item meta in WooCommerce

I am missing something. I have seen several articles about how to update an items meta data but I can't get any one of them to work. I need to get the item_id but I can't figure out how to do that.

$your_phone = $item->get_meta('dinner_phone'); // 1115559999
$update_phone = wdc_format_phone($your_phone); // comes back (111) 555-9999

wc_update_order_item_meta($item_id,'dinner_phone', $update_phone); //I want to update with new format

$new_phone = $item->get_meta('dinner_phone'); // doesn't work I still get 1115559999

I have tried to pull the Item_id by the following

foreach ( $items as $item ) {
    $product_id = $item->get_product_id();
    $item_id = $item['item_id'];
    break;
}

Also tried this

    foreach ($items as $key => $product ) {
      $item_id = $key;
   }

You will use the following from an existing WC_Order Object $order variable:

foreach ( $order->get_items() as $item ) {
    $dinner_phone   = $item->get_meta('dinner_phone'); // 1115559999
    if ( ! empty( $dinner_phone ) ) {
        $formatted_diner_phone = wdc_format_phone( $dinner_phone ); // comes back (111) 555-9999

        $item->update_meta_data('dinner_phone', $formatted_diner_phone);

        $item->save(); // Save item

        $new_phone = $item->get_meta('dinner_phone');
        echo $new_phone; // Check that items is updated
    }
    $order->calculate_totals(); // Recalculate Order totals and save
}

It should work.