You can mute incoming calls on the WebEx softphone in the "Settings" in the "Notifications" area for "Calls". If you select "Always mute notifications", you will not be notified visually (call window) or acoustically of incoming calls. Use this setting for web conferences, for example.
Alternatively, you can also switch off the ringtone only and retain visual notifications (call window). To do this, please turn "off" the sound for call notifications and leave the setting for direct calls at "Don't mute notifications".
If you are in a call pickup group (to be ordered separately from the Service Desk), you can also deactivate notifications for your call pickup group only. To do this, activate the "Mute" option for Call Pickup.