Raffles' agent changed advisory officers (7,5)

I believe the answer is:

general staff

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'raffles' agent changed advisory officers' is the definition.
I can't tell whether this definition defines the answer.

'raffles' agent changed' is the wordplay.
'changed' is an anagram indicator.
'raffles'+'agent'='rafflesagent'
'rafflesagent' anagrammed gives 'GENERAL STAFF'.

Can you help me to learn more?

(Other definitions for general staff that I've seen before include "Military planners" , "Senior officer's aides" , "Commander's assistants" .)

I've seen this clue in The Telegraph.

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