Unit is reorganised without moving (2,4)
I believe the answer is:
in situ
'without moving' is the definition.
(remaining in place)
'unit is reorganised' is the wordplay.
'reorganised' indicates an anagram.
'unit'+'is'='unitis'
'unitis' is an anagram of 'IN-SITU'.
(Other definitions for in situ that I've seen before include "Being in the original position, not having been moved" , "at original location" , "Latin meaning 'on site'" , "At the appropriate location" , "Already placed" .)