How to filters the event by differ date than mapped in sourcetype

We have Date1 mapped in the sourcetype for the index. So if I select last 7 days in the date filter data is filtered on date 1. But for my project I need to use Date2 as a date / duration filter in the dashboard. I cannot change the sourcetype only for my dashboards. Is there any way to make this changes in the settings or code? Sample data Created_Date (Date1) First Name Last Name Task Execution_Date (Date2) 1/12/2017 ABCD XYZ Open Request 12/12/2017 6/12/2017 DDFFG SSV BBB Save the File 12/12/2017 Data has been indexed on Created_Date (Date1) where as I want to use Execution_Date (Date2) as a date filter.