Up to about five hundred crews embrace change (9)

I believe the answer is:

amendment

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'change' is the definition.
(amendment is a kind of change)

I cannot understand how the rest of the clue works.

(Other definitions for amendment that I've seen before include "maybe fifth taken by US criminal" , "Statement added to or revising a document" , "Change designed to improve a text" , "Correction" , "Revision" .)

I've seen this clue in The Times.

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