This region is functions when you want to add a custom field that require to input regions(country/states) for example country and address field. so in will list all the data that you've add here https://www.screencast.com/t/LomghJMvNr
Correct me if I am wrong here, do you mean you want to change the states yes?
You can alter it in the file: .../administrator/components/com_easysocial/defaults/regions/state.json
then in Easysocial backend>regions>states>initialise database: https://take.ms/ni702