How to: Remove the Witness from a Database Mirroring Session (Transact-SQL)

At any time during a database mirroring session, the database owner can turn off the witness for a database mirroring session.

Turning off the witness changes the operating mode in accordance with the transaction-safety setting:

• If transaction safety is set to FULL (the default), the session uses high-protection synchronous mode. For more information, see Synchronous Database Mirroring (High-Safety Mode).
  
• If transaction safety is set to OFF, the session operates asynchronously (in high-performance mode). For more information, see Asynchronous Database Mirroring (High-Performance Mode).
  

The transaction safety setting of the database is recorded on each partner in the sys.database_mirroring catalog view in the mirroring_safety_level and mirroring_safety_level_desc columns. For more information, see sys.database_mirroring (Transact-SQL).