Calling attendant about one, finally (6)
I believe the answer is:
career
'calling' is the definition.
('career' can be a synonym of 'calling')
'attendant about one finally' is the wordplay.
'attendant' becomes 'carer'.
'about' is an insertion indicator.
'finally' indicates one should take the final letters.
The last letter of 'one' is 'e'.
'carer' going around 'e' is 'CAREER'.
(Other definitions for career that I've seen before include "Progression through working life" , "Progress in occupation" , "Whole of employment" , "Run; calling" , "Rush wildly" .)