Hi,

 I have been asked to add a new Exchange server to a Domain, uninstall old Exchange servers (two) and stop using DAG.

 This is te status now:

 I have 3 Exchange servers in a DAG running fine, the servers have all the roles except edge.

 I am wondering what is the best way to do this. Will I get a problem if I uninstall the old Exchange server i.e. regarding Active directory? UM is also configured an used, is there something there I should be aware of?

My Next plan is to remove the old servers from HW LB an make database active on the new Exchange server, then all users should connect to the new server. Remove the old server from the DAG and delete the DB copy. Delete DAG.

Is this a correct and safe way to do this?

It is not my decision to not to use DAG, but I do what I am told :)

thanks.

You basically must remove everything from the server, including mailboxes, connectors, the OAB, etc., and make sure DNS isn't pointing any clients to it, including removing it from load balancing.  Remove the database replicas and remove server from the DAG.  Then you can uninstall it.