When the screen is unlocked you will see the controls shown in the figure above. Follow the 4 easy steps to change the password. If you have want to abandon your changes at anytime, click the 'Revert' button.
If you have changed the password the 'OK' button will only be enabled when both the edit boxes contain exactly the same value. Remember passwords are case sensitive and so 'password' is not considered the same as 'PASSWORD'.