Make reference to appearance in conversation (4)
I believe the answer is:
cite
'make reference to' is the definition.
(I've seen this in another clue)
'appearance in conversation' is the wordplay.
'appearance' becomes 'sight' (synonyms).
'in conversation' shows a homophone (sound like).
'sight' sounds like 'CITE'.
(Other definitions for cite that I've seen before include "Quote as an example or in support" , "Mention as example or quote" , "Summons - quote" , "Quote or refer to" , "Repeat a passage from some written work" .)