By default, the index name is main in Splunk Enterprise. You can modify the default index name, by updating PowerFlex_data macro.
Log in as administrator and select Settings > Advance search > Search Macros.
By default, Dell EMC PowerFlex App for Splunk (dell_PowerFlex_app_for_Splunk) is selected in the App drop-down. A list of available macros is displayed.
Select and edit PowerFlex_data macro and change the definition of macros with new index name.