Replace the organizer on Outlook appointments.

I recently migrated a company from one domain to another, from sbs 2003 to sbs 2008.
After it was complete a couple of users noticed that they could not modify their past appointments or reoccurring appointments in Outlook. They get the error "they are not the organizer of this meeting and do not have permission to modify or delete".

They were the organizer in the old domain. My question is, how do I update all of the past meetings to a new owner in the new domain?

Thanks in advance.