How do I quickly notify previous users of my form? I need to send them a link to another form which is an updated version of this one.

One of your customer service help reps sent me a reply back and helped me get a sign up chart so the RSVPs would be blocked out 1 family per a time slot. So my next question is... I need to take the customers that signed up for my event on my first form and get them on my new form with the chart. 

Thanks for asking. We have an app called Email Newsletters which, once integrated into the first jotform, can be used to notify all customers who signed up via that form. For details on how to use the app, please see this blog post by our founder.

Should you need further assistance, we'd be happy to provide it.

Cheers