l don't know if this is what you are looking for but this will update fields and their values throughout your indexes or index.
POST logstash-*/_update_by_query
{
"script": {
"source": "ctx._source.type='ChangeMeOld'",
"lang": "painless"
},
"query": {
"term": {
"type.keyword": "changeMeNEW"
}
}
}