I have 3 Exchange 2013 servers running on Windows Server 2012R2 in a DAG in hybrid mode to office 365 via a Microsoft Azure AD Sync. User mailboxes are migrated to office 365 when created. I want to either upgrade or decommission these servers. I was looking at decommissioning 2 servers and then do this https://docs.microsoft.com/en-us/Exchange/manage-hybrid-exchange-recipients-with-management-tools , would this work for my situation? Or what would be a better solution?