Conversation is crude so must be changed (9)

I believe the answer is:

discourse

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

'conversation' is the definition.
(I know that discourse is a type of conversation)

'is crude so must be changed' is the wordplay.
'is crude so' can be anagrammed to 'DISCOURSE'.
But, I am not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for discourse that I've seen before include "(Formal) talk" , "Conversation, dialogue" , "To hold a conversation" , "Written or spoken communication" , "Communication verbally" .)

I've seen this clue in The Independent.

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