How to reindex data in Elasticsearch without actually changing index names?

Elastic Stack Elasticsearch
9

So for the last 2 months I can just reindex data and delete old indices. But for the present month I will need to add the alias.

   curl -XPOST localhost:9200/_aliases -H 'Content-Type: application/json' -d '
    {
        "actions": [
            { "add": {
                "alias": "project-2017.10",
                "index": "project-2017.10-1"
            }}
        ]
    }

Please let me know if this is the right approach.