How to change the rotation arcade expression for a SimpleRenderer?

[Anonymous User]

I've created a webmap with a simple renderer that has an arcade rotation expression.

When the map loads with 100.7 WPF, it draws the symbols rotated correctly, and I see the renderer is a SimpleRenderer.

However, I don't see any methods on SimpleRenderer that would allow me to alter the arcade expression.

Is there a Simple way to do this with the SimpleRenderer?