The most common and most likely answer to this crossword clue is the 7 letter word EDITING
I've seen this crossword clue in The Times
E
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Buddy explains!

The straight part
We know that "revision" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case revision = editing.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 EDITING mean?
EDITING verb- To change a text, or a document.
- To be the editor of a publication.
- To change the contents of a file, website, etc.
- To alter the DNA sequence of a chromosome; to perform gene splicing.
- To alter a film by cutting and splicing frames.
- To cut short or otherwise alter an improvised scene.
- To lend itself to editing in a certain way.
- An act or instance of something being edited.