Complex sentence: Company sergeant-majors and their equivalents are normally addressed as "Sergeant-Major" or by rank; by subordinates they are referred to as "Sir", "Ma'am", or "Warrant" (for warrant officers) as appropriate.
Split into simpler sentences: Company sergeant-majors and their equivalents are normally addressed as "Sergeant-Major" or by rank. By subordinates, they are referred to as "Sir", "Ma'am", or "Warrant" (for warrant officers) as appropriate.