Known Password Reset (KPR) allows users to reset their password when they're away from an active directory network. Once it's enabled a link will be visible below the login box where the password can be reset from, providing the current password is known.
To enable self service password reset simply select it from the features list in the portal and click enable and select the classification that you would like to use with it.
To reset a password simply select the link on the login screen and you'll be presented with the option below:
In order for the password resets to write back to AD Destination for passwords needs to be enabled under Active Directory in Applications. It can be enabled by clicking the edit button.