You can allow someone to see the line status of a specific person's phone from the additional line keys on their own phone. Users can also quickly dial a monitored phone simply by pressing the associated line key on their desk phone. You can also enable users to monitor call park extensions, and see if any calls are parked on them.
The maximum number of monitored lines is 50 but you should consider bandwidth. The maximum may also be determined by the number of line buttons on the user's phone.
From the customer view in https://admin.webex.com, go to Users, and select the user you want to modify.
Select Calling, choose Advanced Call Settings, and then go to Monitoring.
Choose from the following:
Choose whether you want this user to be notified about parked calls, search for the person or call park extension to be monitored, and then click Save.