Tries again to go over brief (7)
I believe the answer is:
rehears
'tries again' is the definition.
('hears' can be a synonym for 'tries' so perhaps 'rehears' is OK for 'tries again')
'go over brief' is the wordplay.
'go over' becomes 'rehearse' (I've seen this in another clue).
'brief' means to remove the last letter (a shorter or briefer version of the word).
'rehearse' with its final letter removed is 'REHEARS'.
'to' acts as a link.
(Other definitions for rehears that I've seen before include "Once again tries" , "judges over" .)