Church ceremony set down on paper for reading out (4)
I believe the answer is:
rite
'church ceremony' is the definition.
'set down on paper for reading out' is the wordplay.
'set down on paper' becomes 'write'.
'for reading out' shows a homophone (sound like).
'write' is a homophone of 'RITE'.
(Other definitions for rite that I've seen before include "Custom" , "Uncomplaining person" , "form of service" , "Ceremony, liturgy" , "Customary observance" .)