Question: Upon receiving an HTTP PATCH request from an Application Function (AF) to modify an existing individual Application AM Context resource, how does the Network Exposure Function (NEF) proceed if the AF is authorized?
Option 1: The NEF directly updates the resource and sends a '200 OK' status code with the updated AppAmContextExpRespData to the AF.
Option 2: The NEF interacts with the Policy Control Function (PCF) using Npcf_AMPolicyAuthorization_Update request, and only updates the resource if the PCF responds successfully.
Option 3: The NEF sends a confirmation request back to the AF for additional validation before proceeding with any updates or interactions with the PCF.
Option 4: The NEF denies the request by default due to security protocols and sends a '403 Forbidden' status code to the AF.
Explanation: This is the correct procedure. When an authorized AF initiates a modification request for an Application AM Context, the NEF must ensure policy consistency by interacting with the PCF before updating the resource. This step validates the request against policy rules and ensures the network's integrity. Only upon successful confirmation from the PCF does the NEF update the resource and respond accordingly to the AF.