A global known word/script for undo?

So I was having trouble scripting this script:

script.Parent.Touched:Connect(function()
	script.Parent.Color = Color3.new(255/255,0/255,0/255)

And then I wanted to make it to where it would undo it I tried this script:

script.Parent.Touched:Connect(function()
	script.Parent.Color = Color3.new(255/255,0/255,0/255)
	wait(0.1)
	undo
end)

And then I realized undo is not a global known word in lua Anyone know what it is?

What you need is a previous value

local prevColor = script.Parent.Color
local newColor = Color3.new(255/255,0/255,0/255)
script.Parent.Touched:Connect(function()
    script.Parent.Color = newColor
    wait(0.1)
    script.Parent.Color = prevColor
end)

try that.. It changes the new color to the previous color..