What was that you said to the welcome guest leaving? (4,5)

I believe the answer is:

come again

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'what' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for come again that I've seen before include "Recall" , "eh?" , "Please clarify" , "I don't understand that" , "I'm sorry?" .)

I've seen this clue in the Evening Standard.

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