Ambassador stopping behind to try again (6)
I believe the answer is:
rehear
'try again' is the definition.
('hear' can be a synonym for 'try' so perhaps 'rehear' is OK for 'try again')
'ambassador stopping behind' is the wordplay.
'ambassador' becomes 'he' (His or Her Excellency).
'stopping' indicates putting letters inside (stopping can mean blocking a gap).
'behind' becomes 'rear' ('rear' can be a synonym of 'behind'**).
'he' placed inside 'rear' is 'REHEAR'.
'to' is the link.
(Other definitions for rehear that I've seen before include "Retry (a lawsuit)" , "be a sympathetic listener, not for the first time" , "Try again (in court)" , "Hold the trial again." .)