how to change player nametag?

so i make a brick that will change player nametag but for some reason it display me a error message "19:50:37.871 - Label edit failed : The current identity (0) cannot set a Character's name (requires 4)".

function aaa(part)
	local human  = part.Parent:FindFirstChild("Humanoid")
	if human then
		human.Parent.Name = "AAAa"
	end 
end
script.Parent.Touched:connect(aaa)

is something wrong?