How Do I make a part look at another part using Orientation and NOT CFrame?

How do I make a part look at another part using Orientation? I am aware CFrame exists, but I DON'T want to use CFrame. I need to use orientation. Any advice?

i am not sure if this fits your conditions, but this does not change the CFrame property:

local z, x, y = CFrame.new(origin.Position, target.Position):ToOrientation()

origin.Orientation = Vector3.new(
    math.deg(z),
    math.deg(x),
    math.deg(y)
)

:ToOrientation gives you the orientation of CFrame in radians, you need to convert them to degress using math.deg and i don't know why the order is Z, X, Y, no math genius as you can see.