I put in a call for ventilation (6)
I believe the answer is:
airing
'for ventilation' is the definition.
(synonyms)
'i put in a call' is the wordplay.
'put in' indicates putting letters inside.
'call' becomes 'ring' (telephone call).
'a'+'ring'='aring'
'i' put within 'aring' is 'AIRING'.
(Other definitions for airing that I've seen before include "Ventilating, say a grievance" , "Broadcast" , "excursion" , "Expressing (a grievance) publicly" , "Showing" .)