To reset course course, you need to make sure the course is first set to not be available after completion. Here's how to set course to not be available after completion. Please note that this is a temporary change. Feel free to set the course to be available after completion once you complete the status reset process.
Step 1: Go to Course Settings to turn off Available after completion
Step 2: Turn off Available after completion
Step 3: Go to Course Stats and click the checkbox before the user's name:
Step 4: Click [Reset Completion Status]
Step 5: Feel free to set Available after Completion go on: