(755 ILCS 5/4-9)
(from Ch. 110 1/2, par. 4-9)
Effect of alteration.
An addition to a will or an alteration,
substitution, interlineation or deletion of any part of a will which does
not constitute a revocation of a will is of no effect, unless made by the
testator or by some person in his presence and by his direction and consent
and unless the
will is thereafter signed and attested in the manner prescribed by this
Article for the execution of a will.
(Source: P.A. 81-1509.)