The most common and most likely answer to this crossword clue is the 8 letter word MUTATION
I've seen this crossword clue in The Daily Telegraph
M
U
T
A
T
I
O
N
Buddy explains!

The straight part
We know that "Change" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case change = mutation.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MUTATION mean?
MUTATION noun- Any alteration or change.
- Any heritable change of the base-pair sequence of genetic material.
- A mutant.
- An alteration a particular sound of a word, especially the initial consonant, which is triggered by the word's morphological or syntactic context and not by its phonological context.
- A group of thrushes.