How do you "apply" a shape key?

I mean, you have an object with a shape key affecting it, but you want to keep that intermediate shape, without the shape key. Is there any way to do this?

Ist actually realy simple!
Just select the Mesh, go to the Object Menu / Scrips / Apply Deformation.
This will create a copy of your Mesh and “Bake” the shapekeys in.
Have fun!.

Object mode - Pin the shape key you want to make permanent.
Edit Mode - select all the verts that are effected by the shape key.
Edit Mode - “W” key and select “Propagate to all shapes”
Object Mode - Delete unwanted shape key(s)