Is it possible to have someone submit the form then go back to the same form, edit it and submit it again?

Hello kingsart,

Yes it is possible to achieve your requirement. You may like to add {edit_link} tag in the auto-responder email alert of your form. When the user submits the form, they will receive an auto-responder email which will have a clickable link. Clicking on this link will allow the used to edit their own submission data. The following guide should help you:  http://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date 

Hope this helps.

Do get back to us if you have any questions.

Thank you!