the action or process of changing or adjusting (altering) something, or the state of being thus changed;
e.g. The tailor took measurements for the alteration of the dress.
(noun)
a change or adjustment made to something, especially a change made to a piece of clothing to make it fit better or a significant change made to a document;
e.g. The most major alteration to the jacket was the narrowing of the shoulders. He made an alteration to the contract so that it suited his interests better.