As such there is no direct method to copy or rename index in ES (I did search extensively for my own project)
However a very easy option is to use a popular migration tool [Elastic-Exporter].
http://www.retailmenot.com/corp/eng/posts/2014/12/02/elasticsearch-cluster-migration/
[PS: this is not my blog, just stumbled upon and found it good]
Thereby you can copy index/type and then delete the old one.