Multiple sheet updates for a single Google Form submit

Question

I want a Google Form submission to modify an existing row in a response sheet, rather than produce a new row.

I have a Google Form response sheet and when someone updates a form with the same information a second time (e.g. if they missed out a field, and have a unique ID for each row), is there any way to edit the response sheet so that the already existing row gets modified instead of a new row getting created?

I am completely new to App Script, if you could just point me in the right direction that would be great.

Answer 1

Start with this answer to a similar question: Allow only one Google Form submission per user.

Instead of just deleting a new row if that user had already submitted a form, you can overwrite the previous row. (...and still delete the new one.)