Retrieve a Parent Event or Master Event from Child Events

When you create an event with invitees, two events are created in the backend.
This can be verified by Querying for Event records as below. This will retrieve two records for the same event with the same Subject , one with IsChild=True and the other would have IsChild would have false . 

Select Id, subject, isChild, WhatId, WhoId From Event

But if you'd like to retrieve the parent Event from a given Child Event, unfortunately, there is no easy way. However ,It is possible to create a report with the condition “IsChild” set to “False” that provides a list of parent records.