Is it possible to change ElasticSearch index name?

When I create the index for my Gitlab instance its name is gitlab-production, and that is also said on the documentation but I can’t find where does this name come from. I just need to use the same ES instance with two different Gitlab env. so I just need them to have different indexes otherwise creating an index for Gitlab instance #1 deletes the index from instance #2.

By the way, I am using the Omnibus installation, so whenever I need to create an index I use: “# Omnibus installations
sudo gitlab-rake gitlab:elastic:create_empty_index”

Any ideas?