title: How to find Index by Alias in Elasticsearch php client api
body: <p>I am creating search application. When I reindex data into elasticsearch there should not be downtime while reindexing. I want to make reindexing process with zero downtime.I'm trying to do this:</p>
  
  <p>Find the old index with alias.
  Create new index and fill with new data
  Remove alias and delete old index
  Give new index alias</p>
  
  <p>How we can do this using php client library.</p>