Hey Shauna,
Thanks for your feature request 
From my understanding, you’d essentially be looking to update existing items and columns using forms (i.e. edit information previously submitted via the form)? If this is the case, I can confirm that this is currently a feature we are working on rolling out in the near future.
You can check out the existing feature request here → Use Forms to edit/update existing items and columns
I will be providing updates when more information is shared with me, so stay tuned 