An employee cannot change his own PIN code but any superior can. There are various ways of changing an employee's PIN. It can be done either through an employee's profile or timesheet or even en masse in the employee list.
A) Modifying PINs En Masse
This is the quickest way to change the PINs of several employees.
Go to the "Employee" menu
Change the "Email" column header for "Time and attendance PINs"
Change the PIN's you like by clicking on them
B) Changing the PIN in the employee profile
Go to the employee profile
"Time and Attendance" tab
Change the PIN
C) Changing the PIN in the employee's timesheet
Go to "Time and attendance" menu
Click on the employee to open his Timesheet
Edit the PIN