How to edit Upcoming call

At any time you can click on  Upcoming Call, which has not started yet, and edit it. You can change label, time/date/duration, add/remove participants, change callback number and even delete scheduled call. To do this you have to click on Upcoming Calls page, select a call you want to edit and click on it.

Once, you are on the scheduled call page you can edit details by clicking on appropriate tabs