Meaning of alteration

(noun) an event that occurs when something passes from one state or phase to another; "the change was intended to increase sales"; "this storm is certainly a change for the worse"; "the neighborhood had undergone few modifications since his last visit years ago"

the act of making something different (as e.g. the size of a garment)

the act of revising or altering (involving reconsideration and modification); "it would require a drastic revision of his opinion"