Once you have scheduled the assessment, you can unschedule or modify scheduling. To do so, click the Manage button of your desired course and then click the Instructor Tools button of your desired section.
Click the Assessments tab and then click the settings menu next to the assessment created by you, and select the Modify Schedule or Unschedule option as per the requirement.
If you have selected the Modify Schedule option, provide the required details and click the Save button. If you have selected the Unschedule option, a confirmation modal will open. Click the OK button to unschedule the assessment.