Give second makeover to small church decoration? (7)
I believe the answer is:
reredos
'church decoration?' is the definition.
I don't understand how the rest of the clue works.
(Other definitions for reredos that I've seen before include "Red rose could show a screen behind the altar" , "Fireback" , "Hanging in church" , "Back of fireplace" , "Painted screen behind an altar" .)