title: Elasticsearch Mapping - Rename existing field
body: <p>Is there anyway I can rename an element in an existing elasticsearch mapping without having to add a new element ?
  If so whats the best way to do it in order to avoid breaking the existing mapping?</p>
  <p>e.g. from fieldCamelcase to fieldCamelCase</p>
  <pre><code>{
      &quot;myType&quot;: {
          &quot;properties&quot;: {
              &quot;timestamp&quot;: {
                  &quot;type&quot;: &quot;date&quot;,
                  &quot;format&quot;: &quot;date_optional_time&quot;
              },
              &quot;fieldCamelcase&quot;: {
                  &quot;type&quot;: &quot;string&quot;,
                  &quot;index&quot;: &quot;not_analyzed&quot;
              },
              &quot;field_test&quot;: {
                  &quot;type&quot;: &quot;double&quot;
              }
          }
      }
  }
  </code></pre>