alteration. 1.Property. A substantial change to real estate, esp. to a structure, usu. not
involving an addition to or removal of the exterior dimensions of a building’s structural parts. •
Although any addition to or improvement of real estate is by its very nature an alteration,
real-estate lawyers habitually use alteration in reference to a lesser change. Still, to constitute an
alteration, the change must be substantial — not simply a trifling modification.
structural alteration.A significant change to a building or other structure, essentially creating
a different building or structure.
2. An act done to an instrument, after its execution, whereby its meaning or language is
changed; esp., the changing of a term in a negotiable instrument without the consent of all parties
to it. • Material alterations void an instrument, but immaterial ones do not. An alteration is
material if it (1) changes the burden of a party (as by changing the date, time, place, amount, or
rate of interest), (2) changes the liabilities or duties of any party (as by adding or removing the
name of a maker, drawer, indorser, payee, or cosurety), or (3) changes the operation of the
instrument or its effect in evidence (as by adding words or negotiability, changing the form of an
indorsement, or changing the liability from joint to several). [Cases: Alteration of Instruments
1–30. C.J.S. Alteration of Instruments §§ 2–99, 104–109.]“With respect to written instruments,
‘alteration’ generally means a change in an instrument’s sense of language caused by a party to the
instrument, and does not include such changes by non-parties or ‘strangers’ to the instrument.
Although the distinction is not always observed, technically an alteration by a non-party or
stranger to the instrument is a ‘spoliation,’ not an alteration, which does not invalidate it or change
the rights or liabilities of the parties in interest, so long as the original writing remains legible.” 4
Am. Jur. 2d Alteration of Instruments § 1 (1995).
material alteration. 1. A significant change in something; esp., a change in a legal instrument
sufficient to alter the instrument’s legal meaning or effect. [Cases: Alteration of Instruments 1.
C.J.S. Alteration of Instruments §§ 2–4.] 2. An unauthorized change in an instrument or an
addition to an incomplete instrument resulting in the modification of a party’s obligations. UCC §
3-407(a). [Cases: Alteration of Instruments 1–30. C.J.S. Alte-ration of Instruments §§ 2–99,
104–109.] [Blacks Law 8th]