law: Indian Contract Act, 1872 
   39. Effect of refusal of party to
  
  perform promise wholly
  When a party to a contract has refused to perform, or disabled
  
  himself from performing, his promise in its entirety, the promisee may put an end
  
  to the contract, unless he has signified, by words or conduct, his acquiescence
  
  in its continuance.
   Illustrations 
  (a) A, a singer, enters into contract with B, the manager of a
  
  theatre, to sing at his theatre two nights in every week during next two months,
  
  and B engages to pay her 100 rupees for each night's performance. On the sixth
  
  night A willfully absents herself from the theatre. B is at liberty to put an
  
  end to the contract.
  (b) A, a singer, enters into contract with B, the manager of a
  
  theatre, to sing at his theatre two nights in every week during next two
  
  months, and B engages to pay her at the rate of 100 rupees for each night. On
  
  the sixth night A willfully absents herself. With the assent of B, A sings on
  
  the seventh night. B has signified his acquiescence in the continuance of the
  
  contract, and cannot now put an end to it, but is entitled to compensation for
  
  the damage sustained by him through A's failure to sing on the sixth night.