More help please on using Form

Hi Developers!
In the documentation on Forms here, there is the following:

... results are sent back to the form (or to a redirected page) where messages are displayed and the form can be edited for re-submission if required.

Would someone please give a bit more information (code snippet/example) as to how the form can be edited for re-submission.

Alternatively, a link to a plugin where this has already been done would be fine.

I really need help on this. I’m trying to work through the form.php code to work out a solution, but some help would speed up my work.