demote， break， bust， degrade， downgrade， reduce
The central meaning shared by these verbs is “to lower in grade, rank, or status”:
was demoted from captain to lieutenant; 统领降为副手；
a noncommissioned officer broken to the ranks; 一个被降级衔但还未受任命的军官；
a detective who was busted to uniformed traffic patrol for insubordination;
a supervisor degraded to an assistant; 降为侍者的管理人员；
a popular author downgraded by critical opinion to a genre writer; 因批评性言论被降为专题作者的知名作家；
a captain who was reduced from command of a battleship to administrative duty ashore.