If it is a normal user, you just have to dio the folllowing:
instead of USER, type the name of the user you want to change the passwod
."TEXT"<-- these are the echos from passwd.
Code:
passwd USER
"enter new UNIX password:"type your password, you wish to give.
"retype new password :"retype it
"passwort changed successfull"
well, this is all, what to do
greets
jff