title: Switch billing fields and shipping fields on WooCommerce Checkout Page using hooks and filters
body: <p>I've got a WooCommerce Checkout Page which has the Billing Section on the left (or top, on mobile) and the Shipping Fields on the right (or bottom).</p>
  
  <p>I want to swap these around. I could do this by editing the following code on the form-checkout.php file but I don't want to do that because I don't like editing template files.</p>
  
  <pre><code>    &lt;div class="col2-set" id="customer_details"&gt;
          &lt;div class="col-1"&gt;
              &lt;?php do_action( 'woocommerce_checkout_billing' ); ?&gt;
          &lt;/div&gt;
  
          &lt;div class="col-2"&gt;
              &lt;?php do_action( 'woocommerce_checkout_shipping' ); ?&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>I want to un-hook the relevant function 'checkout_form_billing' from the 'woocommerce_checkout_billing' hook and rehook it into the 'woocommerce_checkout_shipping'.</p>
  
  <p>I've tried this</p>
  
  <pre><code>remove_action( 'woocommerce_checkout_billing', array( self::$instance, 'checkout_form_billing' ) );
  </code></pre>
  
  <p>and</p>
  
  <pre><code>remove_action( 'woocommerce_checkout_billing', 'checkout_form_billing' ) );
  </code></pre>
  
  <p>But neither seems to remove it. Any thoughts much appreciated. </p>