The kb reference is Q178009. The point is "most" and "possible". Read this kb article very closely. Don't try it unless you really really have to make the name change.
As the kb article notes, Microsoft Exchange Server service accounts will need to be reassociated with the new domain name and security settings on all Exchange Server public folders will be lost. Before renaming the domain, use the command line utility Pfadmin.exe to export the public folder security settings to a text file to make reconstruction of the permissions easier.