Answer: Changing Exchange Server 2010 Witness server can be done using the GUI or the shell however I believe it is much simple to do it using the GUI.
To change Exchange Server 2010 Witness server follow the steps below:
Before we start these are the requirements for the Witness Server:
- The witness server can’t be a member of the DAG.
- The witness server must be in the same Active Directory forest as the DAG.
- The witness server must be running Windows Server 2008 R2, Windows Server 2008, Windows Server 2003 R2, or Windows Server 2003.
- A single server can serve as a witness for multiple DAGs. However, each DAG requires its own witness directory.
First we need to set the proper permission on the new witness server.
Note: do this only if the Witness Server is not running Exchange Server 2010.
Add the Exchange trusted subsystems group to the server local administrator group
Open EMC and go to Organization Configuration -> Database Availability Group Tab
Double Click on the DAG
On the DAG settings Change the name of the Witness Server in the Witness server text area, you can also change the Witness Directory if needed.
Finally, Go to the new witness server and check if the new folder was created.