Decouple (6)
(Another definition for unlink that I've seen is " Separate, detach".)
'decouple' is the definition.
(I know that decouple is a more specific form of the action disconnect)
This is all the clue.
(Other definitions for separate that I've seen before include "Take or keep apart" , "Divided -- distinct" , "Move" , "Distinct, not joined" , "solitary" .)