law: Negotiable Instruments Act, 1881 
  56. Endorsement for part of sum due 
  No writing on a negotiable instrument is valid for the purpose
  
  of negotiation if such writing purports to transfer only a part of the amount
  
  appearing to be due on the instrument; but where such amount has been partly
  
  paid a note to that effect may be endorsed on the instrument, which, may then
  
  be negotiated for the balance.