Madame Arcati holds a seance in this Noël Coward play (6,6)
I believe the answer is:
blithe spirit
(Other definitions for blithe spirit that I've seen before include "Comedy" , "written for a lark by poet" , "Phil is bitter (anag) - Noel Coward play" , "Noel Coward play (Madame Arcati)" , "Coward acts" .)