Lokal exchange:
Remove-OrganizationRelationship –Identity “On Premises to Exchange Online Organization Relationship” 
Remove-FederationTrust –Identity “Microsoft Federation Gateway” 
Remove-SendConnector “Outbound to Office 365”

Office365:
Remove-OrganizationRelationship –Identity “Exchange Online to On Premises Organization Relationship”
(Get-OnPremisesOrganization).OrganizationGuid
Remove-OnPremisesOrganization -Identity <id> (Id kan findes på onprem exchange serveren med ( (Get-OrganizationConfig).guid )
Get-IntraOrganizationConnector | Remove-IntraOrganizationConnector

source: http://blogs.technet.com/b/exchange/archive/2012/12/05/decommissioning-your-exchange-2010-servers-in-a-hybrid-deployment.aspx

og http://blog.kloud.com.au/2014/05/05/removing-an-exchange-hybrid-configuration-2/