The Cisco Webex Meetings Desktop App cannot be used to make any changes to appointments that were scheduled using the Webex Meetings app.
When I try to amend a meeting that was planned using a mobile device, I do not see the button in Productivity Tools that allows me to change the parameters.
Solution:
Only the Cisco Webex Meetings app itself or the Webex site can be used to make changes to a meeting after it has been scheduled using the Cisco Webex Meetings app. This behavior was intended all along.