My light flickers, but the material doesn't change. Can you help?

while true do
	script.Parent.PointLight.Enabled = false
	wait(1)
	script.Parent.PointLight.Enabled = true
	wait(.1)
	script.Parent.PointLight.Enabled = false
	script.Parent.Material = Material.Plastic
	wait(.2)
	script.Parent.PointLight.Enabled = true
	wait(2)
	script.Parent.PointLight.Enabled = false
end

Flickering Light? Check. Changing material of part? X. How do I make the material change?