Cannot change material creation menu

Hello, I cannot change the surface menu as seen in the picture. I need to change this to Volume. It is greyed out and I cannot change it to anything else. Does anyone know how to fix this?

Hey there @seanpfett! Welcome to the community! Looks like you have changed your materials to Substrate materials! This means you cannot change the material domain directly. It’s actually controlled in the material by nodes now. Documentation on those nodes below: