title: How to add a new Product details in existing Amazon Order ID in Amazon MWS API
body: <p>I want to add an SKU to an existing Amazon Order.
  My code is as follows:</p>
  
  <pre><code> &lt;AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="amznenvelope.xsd"&gt;
      &lt;Header&gt;
          &lt;DocumentVersion&gt;1.01&lt;/DocumentVersion&gt;
          &lt;MerchantIdentifier&gt;MERCHANT_IDENTIFIER&lt;/MerchantIdentifier&gt;
      &lt;/Header&gt;
      &lt;MessageType&gt;Product&lt;/MessageType&gt;
      &lt;PurgeAndReplace&gt;false&lt;/PurgeAndReplace&gt;
      &lt;Message&gt;
          &lt;MessageID&gt;1&lt;/MessageID&gt;
          &lt;OperationType&gt;Update&lt;/OperationType&gt;
          &lt;Product&gt;
              &lt;SKU&gt;UNIQUE-TO-ME-1234&lt;/SKU&gt;
              &lt;StandardProductID&gt;
                  &lt;Type&gt;ASIN&lt;/Type&gt;
                  &lt;Value&gt;B000A0S46M&lt;/Value&gt;
              &lt;/StandardProductID&gt;
              &lt;Condition&gt;
                  &lt;ConditionType&gt;New&lt;/ConditionType&gt;
              &lt;/Condition&gt;
          &lt;/Product&gt;
      &lt;/Message&gt;
  &lt;/AmazonEnvelope&gt;
  </code></pre>
  
  <p>Above code is to add a new Product but I don't know how to add an item\product to an Amazon orderId.</p>