Exploit upset the person writing this procedure (6)
I believe the answer is:
employ
'exploit' is the definition.
(I know that exploit is a kind of employ)
'upset the person writing this procedure' is the wordplay.
'upset' says the letters should be written backwards.
'the person writing' becomes 'me' (the person writing the clues).
'this procedure' becomes 'ploy' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'me' back-to-front is 'em'.
'em'+'ploy'='EMPLOY'
Can you help me to learn more?
(Other definitions for employ that I've seen before include "Make use of" , "Give work to (person)" , "occupation" , "Put to use" , "Draw on" .)