To edit an exam that has already been created, select the exam from the management page and click Open Exam. This allows the exam to be manipulated like you are able to do when creating a new exam. You can edit individual questions, remove whole sections, add new sections or change other information and attachments.
You can see when a form was last edited. There will be a text line that will inform you of the username and date of the last edit to the exam. Only the information about the most recent edit will be displayed.
These changes will only effect future exam assignments and will not be reflected on previously assigned/completed exams. Make sure to Save any changes you make before exiting the exam editor.