countermand:
transitive verb:
- to revoke (a former command); to cancel or rescind by giving an order contrary to one previously given
- to recall or order back by a contrary order
noun:
- a contrary order
- revocation of a former order or command
Example: Based in a futuristic radar room near Dulles Airport, it has become a master center, with electronic vision that sees every airplane in the system and the authority to question and, in some circumstances, countermand decisions made by individual controllers. [Reference: William Langewiesche, "Slam and Jam", The Atlantic , October 1997]
