Is it possible to have a respondent complete the survey (hit submit), then send them a triggered email saying something along the lines of:
Thank you for your response. If you’d like to update or change your response and/or review your responses, click here [URL to their specific survey]. You may change your responses anytime before [closing date].
When they click on the link they be taken to their survey again with all of their previous responses still selected, and they be able to update their answers.
Yes – check the documentation for details – http://help.surveygizmo.com/help/article/link/send-an-edit-link#automatically-email-respondents-an-edit-link