88. An acceptor or indorser of a negotiable instrument is bound by his acceptance or indorsement notwithstanding any previous alteration of the instrument.
Negotiable Instruments Act, 1881
Section 88: Acceptor or indorser bound notwithstanding previous alteration
Chapter VII — Of Discharge from Liability on Notes, Bills and Cheques
Source: official text of the Negotiable Instruments Act, 1881.