Officer's back in former position (6)
I believe the answer is:
locate
'position' is the definition.
(I've seen this before)
'officer's back in former' is the wordplay.
'officer' becomes 'co' (Commanding Officer abbreviation).
'back' shows that the letters should be reversed in order.
'in' indicates putting letters inside.
'former' becomes 'late' (late can mean former or previous).
'co' written backwards gives 'oc'.
'oc' put into 'late' is 'LOCATE'.
(Other definitions for locate that I've seen before include "Lay one's hands on (something)" , "site" , "spot" , "Discover the place where something is" , "Find out where something is" .)