I am trying to conjugate a symbolic expression, and I have explicitly stated the real terms. However, I simply can't get it to work:

Conjugate[
 ComplexExpand[
  I Cos[z] Sin[y] + Sin[z] + 
   A (Cos[z] - I Sin[y] Sin[z]), {z \[Element] Reals, 
   A \[Element] Reals, y \[Element] Reals}]]

What am I doing wrong here?