Make a small cut and overhaul access codes (4)
I believe the answer is:
snip
'make a small cut' is the definition.
(I've seen this in another clue)
'overhaul access codes' is the wordplay.
'overhaul' says the letters should be written in reverse (I've seen 'overhauled' mean this).
'access codes' becomes 'pins' (PIN numbers for accessing bank accounts).
'pins' written backwards gives 'SNIP'.
'and' acts as a link.
(Other definitions for snip that I've seen before include "Cut with scissors in small strokes" , "Cut with scissors - bargain" , "Surprisingly cheap item" , "bargain buy" , "Bargain (informal)" .)