Sometimes you need to take ownership of a Google calendar item from another user. For instance, maybe someone at your company is in charge of a weekly meeting. When they leave and their account gets deleted, the weekly meeting is suddenly gone, not just from their calendar, but from yours.
The person taking over for the old employee now needs to be in charge of the meeting, so they need to reinstate the old meeting with themselves in charge. If Spanning Backup for Google Workspace is enabled, the user can restore their calendar from a previous version, making sure to restore it with the Attendee List intact. Then they can put the event back on the calendar and change the owner.
Employees coming and going is a fact of life and in order to ensure that the new employee can pick up right where the old one left off, the Google Workspace administrator needs to ensure that they have the proper tools to do so.