law: Negotiable Instruments Act, 1881 
  49. Conversion of endorsement in blank into endorsement in
  
  full 
  The holder of a negotiable instrument endorsed in blank may,
  
  without signing his own name, by writing above the endorser's signature a
  
  direction to pay to any other person as endorsee, convert the endorsement in
  
  blank into an endorsement in full; and the holder does not thereby incur the
  
  responsibility of an endorser.