Administrators have the right to change any user's password at any time using the Strategy Developer interface, but they can also change or reset the password of every user or a group of them by running the following command in Strategy Command Manager:
ALTER USERS IN USER GROUP "<user_group_name>" <new_number_of_days> DAYS <new_expiration_date>];

Therefore, in order to reset every user's password to a default value, the administrator should run:
ALTER USERS IN USER GROUP "Everyone" PASSWORD "" ALLOWCHANGEPWD TRUE;