The word "change" is a synonym for the word "becoming" and an antonym for the word "being." In the entry under Being, I discuss the antithesis between the mutable and the immutable, the realm of the changeable and the realm of the unchanging or permanent. Not everything that is unchanging is eternal or timeless as God is.
Things that come into being and pass away have a permanent being while they are subject to all forms of accidental change, such as change of place, change of quality, and change in quantity. For example, the apple that reddens on the sunlit tree is, from moment to moment, the same apple, otherwise it could not be said to be an identical object undergoing change in color or size.
This leads to the distinction between substantial and accidental change. The birth and death of animal organisms is substantial change; their motions from place to place, their changes in quality and quantity, are accidental changes.
That which changes substantially in coming to be and passing away does not change from being to nonbeing. Substantial change is rather an alteration in mode of being, a kind of transformation, as when a living organism becomes a decaying corpse. In the physical cosmos nothing passes away absolutely; nothing violates the laws of conservation.
The importance of this point is that if the cosmos were ever to cease to be the consequence of this change would be nothingness or absolute nonbeing. That radical change is not a transformation of being, as the decaying corpse is. It is being's negation or denial.
Adler's Philosophical Dictionary (1995)
Great Ideas from the Great Books (1963)
by Mortimer J. Adler