Bills of Exchange Ordinance

Every contract on a bill, whether it is the drawer’s, the acceptor’s or an indorser’s, is incomplete and revocable, until delivery of the instrument in order to give effect
thereto:
Provided that where an acceptance is written on a bill, and the drawee gives notice to or according to the directions of the person entitled to the bill that he has accepted it, the acceptance then becomes complete and irrevocable.