Make another change to grass by centre of site (2-4)

I believe the answer is:

re-edit

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'make another change' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'grass by centre of site' is the wordplay.
'grass' becomes 'reed' (type of grass plant).
'by' is a charade indicator (letters next to each other).
'centre of' says to take the centre.
The middle of 'site' is 'it'.
'reed'+'it'='RE-EDIT'

'to' acts as a link.

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I've seen this clue in The Independent.

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