Summary: Remove calendar events within an Exchange Online mailbox.
Yes there is. There is a newly deployed cmdlet to Office 365 tenants: Remove-CalendarEvents. This cmdlet is currently only available in Exchange Online, but it does allow administrators to remove calendar events, with an attendee, from an owner's mailbox. Here are three examples:
Remove-CalendarEvents -Identity email@example.com -CancelOrganizedMeetings
This example cancels every meeting in the mailbox firstname.lastname@example.org that occurs on or after today's date.
Remove-CalendarEvents -Identity "Angela Gruber" -CancelOrganizedMeetings -QueryStartDate 11-1-2018 -QueryWindowInDays 120
This example cancels the meetings in Angela Gruber's calendar for the specified date range. Angela is taking a temporary leave of absence from the company, so cancelling these meetings removes them from the user and resource calendars during her absence.
Remove-CalendarEvents -Identity "Jacob Berger" -CancelOrganizedMeetings -QueryStartDate 9-1-2018 -QueryWindowInDays 90 -PreviewOnly -Verbose
This example previews the meetings that would be cancelled in Jacob Berger's calendar for the specified date range. No changes are made to the mailbox.