The SCP shall send appropriate "UPS Cancel Requested" N-EVENT-REPORT messages, as described in Section CC.2.4.3 or shall report the appropriate failure response code.

If the Procedure Step State (0074,1000) of the UPS instance is still SCHEDULED, the SCP shall change the Procedure Step State, as described in Section CC.2.1.3, first to IN PROGRESS and then to CANCELED, ensuring that the Final State requirements, described in Section CC.2.5.1.1, are met.

If the Procedure Step State (0074,1000) of the UPS instance is IN PROGRESS, and the SCP is itself the performer of the UPS, the SCP may, at its own discretion, choose to cancel the UPS as described in Section CC.2.1.3.

If the SCP is the performer of the UPS and chooses not to cancel, or if there is no possibility that the performing SCU will be informed of the cancel request (e.g., the subscription list for the UPS is empty, or the SCP has determined that the performing SCU has been disabled), the SCP may return a failure.

Upon completion of the N-ACTION request, the SCP shall return, via the N-ACTION response primitive, the N-ACTION Status Code applicable to the associated request as shown in Table CC.2.2-2.

Bi-directional Authentication of machines/users/applications is possible at association time (see PS3.7 and PS3.15). PS3.7 provides a Failure Status Code of 0124H "Refused: Not authorized". Further requiring or documenting authentication and/or authorization features from the SCU or SCP is beyond the scope of this SOP Class.