Separate notes spoiled chat (6)
I believe the answer is:
detach
'separate' is the definition.
(detaching is a kind of separating)
'notes spoiled chat' is the wordplay.
'notes' becomes 'de' (**).
'spoiled' indicates an anagram.
'chat' with letters rearranged gives 'tach'.
'de'+'tach'='DETACH'
(Other definitions for detach that I've seen before include "Split off" , "His timid love song (T. S. Eliot)" , "Disengage, unfasten" , "Take away -- the cad (anag)" , "Disengage (something) and remove it" .)