Not appropriate, units due to be changed (8)
I believe the answer is:
unsuited
'not appropriate' is the definition.
'units due to be changed' is the wordplay.
'to be changed' is an anagram indicator.
'units'+'due'='unitsdue'
'unitsdue' anagrammed gives 'UNSUITED'.
(Other definitions for unsuited that I've seen before include "Mismatched" , "incompatible" , "United us, not being harmonious" , "United us, being not fit for" .)