Related in revised form (7)

I believe the answer is:

altered

I'm a little stuck... Click here to teach me more about this clue!

'revised form' is the definition.
'altered' can be an answer for 'revised' (I've seen this in another clue). I am unsure of the 'form' bit.

'related' is the wordplay.
'related' anagrams to 'ALTERED'.
However, I'm unsure how the anagram is indicated.

'in' acts as a link.

Can you help me to learn more?

(Other definitions for altered that I've seen before include "Change" , "Metamorphosed" , "Converted" , "Different" , "Reformed" .)

I've seen this clue in the Evening Standard.

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