I need help with a script?

heres my script

local plr = game.Players.LocalPlayer
repeat wait() until plr and plr.Character

local char = plr.Character
local head = char:WaitForChild("Head")
local sg = Instance.new("BillboardGui", char)
sg.StudsOffset = Vector3.new(0,1.5,0)
sg.Size = UDim2.new(1,0,1,0)
sg.Adornee = head

local txt = Instance.new("TextLabel", sg)
txt.BackgroundTransparency = 1
txt.TextColor = BrickColor.random()
txt.Font = "ArialBold"
txt.FontSize = "Size18"
txt.Text = plr.Name -- player name
txt.Size = UDim2.new(1,0,1,0)

but how do I make it to where the characters name no longer shows up?