How to change text of a TextLabel on bilboard?

So I am trying to make a sign, with a GUI in which you can change the text. There is a textlabel in a bilboardGUI in Workspace, but the text of the text box won't change when I type something into it, therefor the text of the textlabel just goes blank. Here's the text:

script.Parent.MouseButton1Click:Connect(function()
    newText = game.Workspace.Shop.Sign.TextBil.SignText:Clone()
    newText.Parent = game.Workspace.Shop.Sign.TextBil
    newText.Name = "NewText"
    newText.Text = script.Parent.Parent.NewName.Text
    game.Workspace.Shop.Sign.TextBil.SignText:Destroy()
    script.Parent.Parent.Visible = false
end)