POST _reindex?wait_for_completion=false
{
  "source": {
    "index": "winlogbeat-*"
  },
  "dest": {
    "index": "winlogbeat"
  },
  "script": {
    "lang": "painless",
    "source": "ctx._index = 'winlogbeat-' + (ctx._index.substring('winlogbeat-'.length(), ctx._index.length())) + '-1'"
  }
}