Explosive change I implement (6,4)
I believe the answer is:
limpet mine
'explosive' is the definition.
(I've seen this before)
'change i implement' is the wordplay.
'change' indicates an anagram.
'i'+'implement'='iimplement'
'iimplement' anagrammed gives 'LIMPET MINE'.
(Other definitions for limpet mine that I've seen before include "explosive" , "Cause of damage in Hull" , "Hull blown up using this" .)