Degrade, demote, reduce, declass, disrate mean to lower in station, rank, or grade.
Degrade may be used of any such lowering. It usually implies a real or presumed fault in what is acted on and often adds to the basic meaning a suggestion of humiliation (see degrade under ABASE). It sometimes denotes a formal or ceremonial stripping (as of a priest or a military officer) of outward evidences of station or rank.
Demote in itself and as distinct from its context does not imply fault to or humiliation of the one demoted.
Reduce (see also DECREASE and CONQUER) never wholly loses its basic sense of to make less or smaller; it denotes a lessening in status or dignity whether involving an actual lowering in rank or not.
Declass is typically used with respect to social classes; it may imply a loss of social position especially as a result of one’s own actions.
Perhaps more frequently it may imply an altering of or a freeing from the restrictions of social status.
Disrate implies a reduction in military and more especially in naval or nautical rank and is used chiefly with reference to petty or noncommissioned officers.