Owl in here? A change is needed to accommodate one (6)
I believe the answer is:
aviary
'owl in here?' is the definition.
(an owl might live in an aviary)
'a change is needed to accommodate one' is the wordplay.
'change' becomes 'vary' (synonyms).
'is needed' says to put letters next to each other.
'to accommodate' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'a'+'vary'='avary'
'avary' placed around 'i' is 'AVIARY'.
(Other definitions for aviary that I've seen before include "Large cage for birds" , "Bird house" , "Bird enclosure" , "Large birdcage" , "Large bird cage" .)