Conjuror's expression (3,6)
I believe the answer is:
hey presto
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">conjuror's expression</span>' is the definition.<br/ ><span class="explanation-format__explanation">(expression a conjuror or magician might use)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for hey presto that I've seen before include "Spell words" , "Conjurer's exclamation" , "revealing remark?" , "tricky words?" , "that's the trick" .)