Needlewomen making a mess changing locks (12)

I believe the answer is:

seamstresses

'needlewomen' is the definition.
('seamstress' can be a synonym of 'needlewoman')

'a mess changing locks' is the wordplay.
'changing' indicates anagramming the letters.
'locks' becomes 'tresses' (I've seen this before).
'a'+'mess'='amess'
'amess' is an anagram of 'seams'.
'seams'+'tresses'='SEAMSTRESSES'

'making' acts as a link.

(Another definition for seamstresses that I've seen is " they create?".)

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