A step in trade reform (5)
I believe the answer is:
tread
'a step' is the definition.
(I know that step can be written as tread)
'trade reform' is the wordplay.
'reform' indicates an anagram (letters in a new form).
'trade' with letters rearranged gives 'TREAD'.
'in' acts as a link.
(Other definitions for tread that I've seen before include "Put one's foot down!" , "dance" , "Top surface of a stair step" , "Tyre moulding" , "March" .)