Automation compare dates in two columns

John Doee
John Doee
edited 12/09/19 in Smartsheet Basics

Hello, I am new to SmartSheet and is playing around with the new automation system

I have 2 columns start date and end date, I want to create an alert to some people that if the start date goes past end date and at the same time make end date blank.  From what I can see I can only compare a date column with a specific date and not able to compare it to other date column.  I would love to have some insights or directions to go about this problem.  Thank you.