Negotiable Instruments Act Section 49 — Conversion of indorsement in blank into indorsement in full
CHAPTER IV OF NEGOTIATION
General
Summary
If you are holding a negotiable instrument that has been endorsed in blank, meaning it is payable to whoever holds it, you can turn that blank endorsement into a full endorsement. You do this by writing, above the original endorser's signature, a direction that the payment should go to a specific person. You do not need to sign your own name to do this, and by making this change, you do not take on the legal responsibilities of an endorser yourself.
Official Text
The holder of a negotiable instrument indorsed in blank may, without signing his own name, by writing above the indorser’s signature a direction to pay to any other person as indorsee, convert the indorsement in blank into an indorsement in full; and the holder does not thereby incur the responsibility of an indorser.