A closer look at Changing the Guard at Buckingham Palace. Changing the Guard or Guard Mounting is the process involving a new guard exchanging duty with the old guard. The Guard which mounts at Buckingham Palace is called The Queen’s Guard and is divided into two Detachments: the Buckingham Palace Detachment (which is responsible for guarding Buckingham Palace), and the St. James’s Palace Detachment, (which guards St. James’s Palace). These guard duties are normally provided by a battalion of th