I'm trying to delete a Site in ServiceDesk Plus (site name = Bordeaux)

When I go to delete this site, I am presented with the following box:

I assumed this meant that it was going to update the Site field of all requesters with the Site of my choosing (in this example I'm going with 'France')

However, when I look back at a ticket logged by a requester at this site, it has remained as Bordeaux

If I raise a new ticket in the requesters name, it pulls through the new site details (however I had already changed the Site on the user as it pulls from Active Directory, so this effectively makes this option useless)

It would appear that historical tickets are not updated when you delete a site.  Is there anyway this can be done?