How do I send a cancellation to attendees for a recurring meeting series that is no longer on the organizer's calendar?

I sent a meeting invite on behalf of my boss.  I, at a later date, due to several people leaving the company and changing the topic and how often the meeting would be occuring, sent what I thought was a cancellation/update to everyone on the original invite.  I must have clicked on send to only deleted attendees.  Now the original invite is no longer on my boss' calendar and I cannot find it in my deleted items anywhere. 

Hi,

On the level of Outlook, we don't have an easy way to cancel this meeting for all attendees, we need to remove this meeting from each invidual's Calendar manually.

Or we can try to do this on the Exchange level. Please refer to this thread below:

https://social.technet.microsoft.com/Forums/office/en-US/cc46985a-d46c-4673-99e5-9685e029409e/how-do-i-delete-a-recurring-meeting-from-all-attendees-after-originator-deleted-the-original-without?forum=exchange2010

The customer in the thread resolved it by "recursively search mailboxes in the mail store to find the items that fit the selection criteria" with the New-ExportMailboxRequest cmdlet. Since I'm not an expert about Exchange, you can post this question in the Exchange forum to ask for advice:

https://social.technet.microsoft.com/Forums/office/en-US/home?category=exchangeserver

Regards,

Melon Chen
TechNet Community Su