Unable to uninstall exchange 2007

I am trying to uninstall a Exchange 2007 server that is in the same forest as a Exchange 2003 server. I'm getting the following error:
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Mailbox Role Prerequisites
Failed

Error:
Uninstall cannot proceed. Database 'Public Folder Database': The public folder database specified contains folder replicas. Before deleting the public folder database, remove the folders or move the replicas to another public folder database.
Recommended Action: http://go.microsoft.com/fwlink/?linkid=30939&l=EN&v=ExBPA.3&id=b6e3b32a-8848-46cb-9567-72288ac15f60
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I can see that its some of the system folders that are set up to replicate with the Exchange 2003 server. But I can't find the Exchange Management Shell command to remove the replicas.