title: Can't Update Record Using Route53 API
body: <p>I've setup a proper request to Amazon Route53 to create a new resource record.  This works flawlessly.</p>
  
  <p>However, now I want to simply change the value of that record.  When I make the same request again with the new value, I get an exception with the following message.</p>
  
  <blockquote>
    <p>Tried to create resource record set [name='my.test.domain.', type='A']
    but it already exists</p>
  </blockquote>
  
  <p>In both requests, I've set the <code>Action</code> parameter to <code>CREATE</code> as the only alternative is <code>DELETE</code>.</p>
  
  <p>I am using the PHP SDK's <a href="http://docs.aws.amazon.com/aws-sdk-php/latest/class-Aws.Route53.Route53Client.html#_changeResourceRecordSets" rel="nofollow"><code>changeResourceRecordSets</code></a> method, which starts it's description like...</p>
  
  <blockquote>
    <p>Use this action to create or change your authoritative DNS
    information.</p>
  </blockquote>
  
  <p>Elsewhere in the Amazon Web Services documentation, I also found the following snippet...</p>
  
  <blockquote>
    <p>If a resource record set does exist, Amazon Route 53 updates it with
    the values in the request. Amazon Route 53 can update an existing
    resource record set only when all of the following values match: Name,
    Type, and SetIdentifier (for latency, weighted, and failover resource
    record sets).</p>
  </blockquote>
  
  <p>Does this mean I <strong>need</strong> the <code>SetIdentifier</code> parameter?  I don't have that since these are latency, weighted, or failover records.  Or are those the only records that can be updated like this?</p>