Live it up, taking in a show (6)
I believe the answer is:
reveal
'show' is the definition.
(I know that reveal is a more specific form of the action show)
'live it up taking in a' is the wordplay.
'live it up' becomes 'revel' (I've seen this in another clue).
'taking in' means one lot of letters goes inside another.
'revel' going around 'a' is 'REVEAL'.
(Other definitions for reveal that I've seen before include "Open up" , "Show, uncover" , "Make known, expose" , "Final disclosure" , "Make known to others" .)