Updating an analyzer like stop word in a template - downtime info needed

Hi,

We are trying to get some info on the stop words (inline) template changes for all index.
How much is the downtime? We know it is just 3 curl command close index, change analyzer in template and open the index.

Please let me know, if we should have stop words in a file, does that also need us to reboot elastic node?

Thanks,
Rahul