override - noun

a manually operated device to correct the operation of an automatic device

the act of nullifying; making null and void; counteracting or overriding the effect or force of something

override - verb

• rule against
• prevail over
• counteract the normal operation of (an automatic gear shift in a vehicle)
• ride (a horse) too hard

override - thesaurus

nullification   overrule   overthrow   overturn   reverse