You can change your Active Directory password on the macOS.  Changing your Active Directory password will change it for all computers and services that use Active Directory.

1.  Login with your AD acct.  (firstname.lastname)


2.  From the Apple Menu in the top Left, select System Preferences.




3.  Click on the Accounts button in the lower left.


4.  Click 'Change Password'



5.  Enter your old password once and your new password twice.  Click 'Change Password'  to save.