Looking for Suggestions on Creating Signup Form

Hi. In a volunteer signup database consisting of names and dates, if a user fills out a form to volunteer on a particular date, and that date has reached the maximum number of volunteers, is there a way to provide a "waitlist" option to appear on the same form that has already been filled out?

Example, I fill out a form to volunteer on Thursday, 7/24, but that particular date already has enough volunteer signups. I would like to get on a waiting list. Can this be done without losing information I have already entered?