If you have DBA or PERMS ADMIN authority, you can change the password of any existing user.
ALTER USER userid IDENTIFIED BY password
If you inadvertently enter the user ID of an existing user when you mean to add a new user, you are actually changing the password of the existing user. You do not receive a warning because this behavior is considered normal. This behavior differs from pre-Version 12 Sybase IQ.
To avoid this situation, use the sp_iqaddlogin system procedure or the CREATE USER to add users. You may also use the sp_addlogin and sp_adduser system procedures. These procedures give you an error if you try to add an existing user ID, as in Adaptive Server Enterprise and pre-Version 12 Sybase IQ.
You can set up password rules and verify that any new password assigned complies with them. For example, you might require that passwords must include one digit or must not be the user ID. For details, see the VERIFY_PASSWORD_FUNCTION option in Reference: Statements and Options.
To set a minimum password length, see MIN_PASSWORD_LENGTH option in Reference: Statements and Options.