Using CFrame.lookAt

How would I use CFrame.lookAt to only change the y axis

                    AC:SetPrimaryPartCFrame(CFrame.new(Vector3.new(0,0,0),CFrame.Angles(0,CFrame.lookAt(AC.Position,part.Position),0)))
local xz = Vector3.new(1,0,1)
local y = Vector3.yAxis
local position --set to a vector3
local target --set to a target vector3
local lookat = CFrame.lookAt(position, (target * xz)+(position*y))

I think you mean X and Z? Why would you need to change the Y?