This will allow the system to check the time zone of a lead based on the area code or state.
You can configure this under Global Settings.
From the Admin dashboard, click on Account and select Global Settings.
Look for Area Code or State Time Zone Conversion, from here you can switch it to State or Area Code.
When set to Area Code the lead's timezone will be set based on the phone number's area code every time a lead is created or updated.
When set to State, the lead's timezone will be set based on the state data included in the lead, when the lead is created or updated. With this setting, if a lead doesn't have any state information, then we'll default to the area code.