[Samba] change samba access password

[tecnobitpa]

Hi,
I ask an, elementary for you, but important for me beginner, problem.
I have samba 2.2.1 with w98 SE client (suse 7.3 system as PDC).
I set unix passwd sync parameter to yes, security to user (smb.conf).
If i set the dead time of password of the system to 90 days and alert time to 7 days, How the samba, or the system, can comunicate to win98 the password alert?
how can i change the password from w98? wich password the system password or the samba password?
Thank you for the answers.
Antonio