code: public static URI getRequestUri(Response response, AddressFactory addressFactory) throws ParseException {
  		final ContactHeader contact = ((ContactHeader) response.getHeader(ContactHeader.NAME));
  		return (contact != null) ? (URI) contact.getAddress().getURI().clone() : null;
  	}
docs: Forges Request-URI using contact and To name par to address URI, this is
  required on dialog fork, this is how target is determined
  
  @param response
  @return
  @throws ParseException