How to cast a ray in the direction of a characters head?

I've been trying to get a part to create rays in the direction of a characters head but i can't find anyway to do so. I've tried Cframe:Lerp but it ends up saying that CFrame expected (Got Vector3) and when i change it to Vector, it says CFrame expected (Got CFrame)

Question: How do I cast a ray towards someones head, I have the head and the part defined, I know how to cast rays but not in the direction required, does anyone know the correct way to do this?