Disengage, separate (6)
I believe the answer is:
detach
I believe this is a double definition.
'disengage' is the first definition.
(I've seen this in another clue)
'separate' is the second definition.
(detaching is a kind of separating)
(Other definitions for detach that I've seen before include "Separate one part from another" , "free" , "His timid love song (T. S. Eliot)" , "Remove from contact" , "The reverse of 11 Down" .)