Need to clear text boxes before submit the form

Hi,

I have a form (Developed using Nintex) in which if an end user check (Yes) the Checkbox, need to enable two textboxes. If they uncheck (No), need to disable. This task I have implemented using 'Add Formula' in Nintex.

In the event an end user checked the checkbox and enters the data in textboxes then switches to Unchecked and then submits the form -- the textboxes are left populated and the data saving into the list. Now, I need to clear the textboxes when the user decided to uncheck and submit the form.

Thanks in advance.