To change a user's status in the course units manually, login as administrator and visit the course which you want to edit the user's status in the course units. Visit the User tabs of the course, which will display you a tabular list of all users assigned to the course.
To manually change a user's status in the course units, click on the units progress option (1) under the operations column. This will open a pop up listing all units of the course.
For each unit you can select to change the status of the user in the unit (2) to either completed, failed or pending.