Splunk stores timestamps as UTC internally and converts them to the user's selected time zone when displayed. No provision is made for a dashboard to display times in a specific time zone.
You could use the relative_time function to subtract hours from IST to make it look like PST, but this would need to be updated every time either IST or PST started or ended Summer Time.
is there any way to changes in xml source file and can show text field value as current IST and PST date time?