Undercover family needs it to change (11)
I believe the answer is:
clandestine
'undercover' is the definition.
('clandestine' can be a synonym of 'undercover')
'family needs it to change' is the wordplay.
'family' becomes 'clan' (I've seen this before**).
'to change' indicates anagramming the letters.
'needs'+'it'='needsit'
'needsit' is an anagram of 'destine'.
'clan'+'destine'='CLANDESTINE'
(Other definitions for clandestine that I've seen before include "Concealed" , "backroom" , "Done secretively" , "through the backdoor" , "Private" .)