Thank you Rachit for the response. Checking for null is something that I did not know. I added the expression like the way you have mentioned in the Validate rule and it doesn't allow me to save. It gives me error.
I have another condition. I have added these Required Condition to all the controls in the page and the validations get fired once the submit is clicked. I have another requirement to have a button to Restart the Stage. So if that button is clicked and Submit is clicked, the user should be redirected to the first step of the Stage. And this should happen irrespective of whether all the control have value or not. i.e. I want to suppress the Required field validations on Restarting the Stage but they should be active for moving to the next step. Any help on how I can achieve this?