Like with anything in life, mistakes happen. Same thing applies to clock times. Whenever they happen it will be necessary to modify them, here's how to do so.
A) Find the time entry
Go to the "Time and attendance" menu
Select the pay period
Click on the employee name
Go to the lower part of the page to see the detail of the employees pay period.
IMPORTANT
You can create a time entry from scratch by clicking in an empty spot where the time entry would be.
B) How to modify
Click on the desired time entry in the "Clocked hours" column
See the following example on the October 28th where Edith forgot to clock out.

When in the time entry, you can use the scheduled start and end (Pink box) or
Enter manually the time (green box)
Save / Approve

Extra tip : Under the tab "Logs" of each time entry you can follow every modification !