Witness Server and Witness Directory are the most critical components of the Database Availability Group (DAG). DAG requires Witness Server or File Share Witness (FSW) and Directory to maintain the Quorum. In case of Witness Server failure, the Quorum is no longer maintained, leading to inconsistent DAG. In addition, the cluster may no longer respond or work, leading to downtimes if a disaster strikes.
However, you can change the Witness Server and Witness Directory to maintain the Quorum and ensure high availability when the Witness Server has failed, is unavailable, or does not boot.