Changing fate is a stunt (4)
I believe the answer is:
feat
'stunt' is the definition.
(I've seen this in another clue)
'changing fate' is the wordplay.
'changing' is an anagram indicator.
'fate' with letters rearranged gives 'FEAT'.
'is a' acts as a link.
(Other definitions for feat that I've seen before include "Achievement needing skill, strength, etc." , "Achievement needing great courage or skill" , "Notable act" , "Notable achievement" , "Exploit; achievement" .)