title: Updating the AttachmentPart contents without creating new message
body: <p>I need to update the AttachmentPart contents inside a SOAPMessage as shown in following figure. I need to keep the headers same.<br>
  Is it possible to do it without creating a new SOAP message? I am using SAAJ APIs.</p>
  
  <p><img src="https://i.stack.imgur.com/YyKc9.png" alt="enter image description here"></p>