The manner of the fellow has changed when I take over (7)
I believe the answer is:
fashion
'the manner' is the definition.
(synonyms)
'the fellow has changed when i take over' is the wordplay.
'the fellow' becomes 'f' (abbreviation - of a society etc.).
'changed' is an anagram indicator.
'when i take over' becomes 'ion' (I can't explain this - if you can you should believe this answer much more).
'has' with letters rearranged gives 'ash'.
'f'+'ash'+'ion'='FASHION'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for fashion that I've seen before include "the latest thing" , "Vogue, style" , "Haute couture" , "Current popular style" , "Ton" .)