Unity C# Post XML to endpoint

Hi,

I have some formatted xml which I wish to post to an endpoint and then read through the response. It is simply the sending to the endpoint and retrieving the response that I am struggling with. This is my XML:

 <auth xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   <auth>
     <passcode>1234</passcode>
     <macaddress>64:20:0c:83:46:BD</macaddress>
   </auth>
 </auth>

Any ideas of the simplest ways? I will be wanting to preferably use the same piece of code to send different xml to different endpoints.

Many Thanks in Advance