Rescind

v. cancel, void, annul, revoke, repeal; remove, take away

In contract law, rescission (to rescind or set aside a contract) has been defined as the unmaking of a contract between the parties. Rescission is the unwinding of a transaction. This is done to bring the parties as far as possible to the position they were before they entered into a contract (the "status quo ante"). This an equitable remedy and is discretionary. The court may decline to rescind a contract if one party has affirmed the contract by his action (see Long v Lloyd [1958] 1 WLR 753) or a third party has acquired some rights or there has been substantial performance in implementing the contract.
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Verb
1. annul by recalling or rescinding; "He revoked the ban on smoking"; "lift an embargo"; "vacate a death sentence"
(synonym) revoke, annul, lift, countermand, reverse, repeal, overturn, vacate
(hypernym) cancel, strike down
(hyponym) renege, renege on, renegue on, go back on
(derivation) recission, rescission

(v. t.)
To cut off; to abrogate; to annul.
  

(v. t.)
Specifically, to vacate or make void, as an act, by the enacting authority or by superior authority; to repeal; as, to rescind a law, a resolution, or a vote; to rescind a decree or a judgment.
  

To cancel a contract because of misrepresentation, fraud, or illegal procedure.