Give uses to change or view Time and Date settings when they are in user level privilege.
Click Start, Run and type GPEDIT.MSC
User Rights Assignment
Double-click “Change the system time”
Add “Administrators” and “Power Users” to the list.
You may and any users or groups to list to the do the job.
No need to reboot the desktop just execute this from RUN tab gpupdate /force to save changes.
Note : Make relogin the added user to get previlage.