Section: 5.5.1.2 Alternate party charging for IMS
Content: This applies to the alternate charged party in charged party principles defined in TS 22.115[ Service aspects; Charging and billing ]  [101]. In IMS offline and online charging as an alternative it is possible that neither calling nor called party can be charged for the IMS session. The alternate charged party need not be registered at the time that the charges are made. It is required however, that the alternate charged party be a verifiable charged party. Selection and verification is done through internal actions in the SIP-AS. The Subscription Identification contains the identity of alternate charged party. The IMS session is then processed in the normal manner. NOTE: The method for verifying the alternate charged party is not covered in the present document.