How to manage a bookings site after the owner leaves the organization

Kreera_House I struggled with initially to find the bookings mailbox name.  To find it, go to the Bookings Page and under "Share your page" you can see the email account name created for your site in the share URL.  The issue I had is these accounts don't show up in ECP, and initially I didn't realize they were a specific RecipientTypeDetails value.  

With that, you can also use this to get all your Bookings mailboxes:
Get-Mailbox -ResultSize Unlimited | Where {$_.RecipientTypeDetails -eq 'SchedulingMailbox'}