Warrant Officer
From Starbase 900 Wiki
Warrant officers are highly skilled, single-track specialty officers. For appointment to Warrant Officer, a warrant is approved by the secretary of the respective service. For Staff Warrant Officer, Master Warrant Officer and Chief Warrant Officer these are commissioned by the President of the Federation and take the same oath as regular commissioned officers in Starfleet (O-1 to O-10).
Warrant officers can, and do, command detachments, units, activities, vessels, aircraft, and armored vehicles as well as lead, coach, train, and counsel subordinates. However, the warrant officer's primary task as a leader is to serve as a technical expert, providing valuable skills, guidance, and expertise to commanders and organizations in their particular field.