Time to change a little bit (4)
I believe the answer is:
mite
'a little bit' is the definition.
(I've seen this in another clue)
'time to change' is the wordplay.
'to change' indicates anagramming the letters.
'time' anagrammed gives 'MITE'.
(Other definitions for mite that I've seen before include "The widow's small offering" , "Minute arachnid" , "Old piece" , "Tiny arachnid, person or amount of money" , "Microscopic creature" .)