On my macbook, running OSX Mavericks, my daughter has a standard-user account.
I wanted to show her how to change her login password under:
SystemPreferences > Users & Groups > ChangePassword
That button was greyed out, even after the padlock was opened.
Note: she is under parental control, but even after I temporarily lifted that, changing the password was not possible.
Any ideas, on how to allow my daughter to change her login password?