Change for the worse (8)
I believe the answer is:
reversal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">change for the worse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(eg a reversal of fortunes)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for reversal that I've seen before include "A set-back or backwards movement" , "A change to an opposite direction" , "Set back" , "U-turn" , "A turning backwards" .)