How to move a Calendar from one mailbox to another.

I have just migrated a company running Exchange 2003 to Exchange 2010.  Exchange 2003 does not utilise resource mailboxes and as a result, my customer has created a bunch of ordinary mailboxes to represent meeting rooms.  As of Exchange 2007 Microsoft introduced resource mailboxes to represent meeting rooms and equipment.

My customer now needs to either create new resource mailboxes to represent the meeting rooms or convert the existing shared mailboxes into room mailboxes.

How to migrate calendar data from one mailbox to another mailbox

In the event my customer chose to create new mailboxes to represent his meeting rooms it is possible to migrate just the calendar information from the existing shared mailboxes to the room mailboxes by using the following powershell commands:

Export the calendar data from one mailbox:

New-MailboxExportRequest -Mailbox "Ex2003SharedMailbox" -IncludeFolders "#Calendar#" -FilePath \\servername\c$\Ex2003SharedMailbox.pst

Import the calendar data into the new mailbox:

New-MailboxImportRequest -Mailbox "NewRoomMailbox" -IncludeFolders "#Calendar#" -FilePath \\servername\c$\Ex2003SharedMailbox.pst

How to migrate the shared mailboxes into room mailboxes

In the event my customer wants to convert the existing shared mailboxes into room mailboxes this can be done with the following command:

Set-Mailbox MailboxName -Type Room