In Exchange Server users can change the user's mailbox password through the user's OWA (Outlook Web Access) settings page or the EAC (Exchange Administration Center) administrator. It is fairly easy to change the password from the user's OWA settings. However, if you want to reset the password of a specific user from the EAC, you may not find the password reset option in the web console. For more info on Reset Microsoft Exchange Password follow the provided link.