Is there a way to edit a submitted form?

Someone who submitted a form wants to edit one of her answers. Is there a way I can do this on the back end, or she can do it herself? Or does she need to fill out a completely new form? 

You may do both, here are the guides that will help you doing so: 

https://www.jotform.com/help/325-How-to-Edit-Submissions-Made-on-Your-Forms

https://www.jotform.com/help/40-How-to-Let-Users-Update-Their-Form-Submissions-at-a-Later-Date 

If you have questions, let us know.