The Virtual clock setting is what prevents employees being able to change their clock in/out times on an individual basis. To learn more about how timesheets work with or without virtual clock, please see:
To turn on/off 'Virtual Clock':
Go to the employee's record
Click into their planner
Select the blue 'Settings' button
Tick/Untick the virtual clock tick box.
Enter a reason for the change.
Customer Services Team.