coun ‧ ter ‧ mand /ˌkaʊntəˈmɑːnd, ˈkaʊntəmɑːnd $ ˌkaʊntərˈmænd/ BrE AmE verb [transitive] formal
[ Date: 1400-1500 ; Language: French ; Origin: contremander , from contre- ( ⇨ ↑ counter- ) + mander 'to command' (from Latin mandare ) ]
to officially tell people to ignore an order, especially by giving them a different one:
Terrorists tried to force him to countermand the order to attack.