Ringing to reveal vocation (7)
I believe the answer is:
calling
I believe this clue is a double definition.
'ringing' is the first definition.
('call' can be a synonym of 'ring')
'vocation' is the second definition.
(synonyms)
'to reveal' acts as a link.
(Other definitions for calling that I've seen before include "Running a bingo game" , "Urge to follow a particular career" , "Predicting the outcome" , "Occupation" , "Ringing" .)