There is no automatic way to do this.

You can use the quiz report to delete the student's attmpt, so they can start again from the beginning.

If you really know what you are doing, then you can manually edit the data in the database to undo what happens when a student clicks 'Sumbit all and finish', but you need to really understand this: https://docs.moodle.org/dev/Overview_of_the_Moodle_question_engine#Detailed_data_about_an_attempt. I would not recommend it.