Any call for it means changes in part (12)

I believe the answer is:

fractionally

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'changes in part' is the definition.
The definition suggests an adverb which matches the answer.

'any call for it' is the wordplay.
'any call for it' anagrams to 'FRACTIONALLY'.
But, I am not sure how the anagram is indicated.

'means' acts as a link.

Can you help me to learn more?

(Another definition for fractionally that I've seen is " A little".)

I've seen this clue in The Globe and Mail.

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