Removing Delegate Calendar Permissions In Exchange Using Powershell

Recently I have been asked to resolve a bunch of erroneous bounce-backs in Outlook. It has been found that an assistant who was a delegate for a bunch of users calendars had offboarded, yet they were still set as a delegate on the users calendar. When going through the Exchange Admin it is impossible to find this setting so you are left with nothing to work with if you are looking for a solution through a GUI. The best way to resolve this is through Powershell

First connect to Exchange Online

Install-Module ExchangeOnlineManagement
Import-Module ExchangeOnlineManagement
Connect-ExchangeOnline

Then run the following command to confirm the user is a delegate for the mailbox

Get-MailboxFolderPermission user@example.com:\Calendar

To remove the permission run this command:

Remove-MailboxFolderPermission user@example.com:\Calendar -User delegateUser@example.com

And back to happy days!