All the employees at AB Corp. need to track their project effort in a file called TimeTracking. Each employee is given a specific time when they have the write permission for that file. Other than the specified time, the file will be in read only mode for them. Ed Young, an employee, needs to leave the office before the time specified to fill the TimeTracking file. Therefore, Ed requests Don Allen, the system administrator, to provide write access to the file. Which of the following commands should Don use to perform this task?