Negotiable Instruments Act, 1881
39. Suretyship
When the holder of an accepted bill of exchange enters into any
contract with the acceptor which, under section 134 or 135 of the Indian
Contract Act, 1872 (9 of 1872), would discharge the other parties, the holder
may expressly reserve his right to charge the other parties, and in such case
they are not discharged.