Yes, confirmation messages (autoresponders) can be resent when form submissions are edited by users after delivery. To have the confirmation message resent, go to the Settings → Advanced section.The option Allow respondents to edit delivered submissions at a later time should be already enabled. All that is left to do is enable the option Resend confirmation message (autoresponder) every time the submission is edited.
Press Save at page bottom. Users will receive the confirmation message each time they edit a delivered submission.