How would I make a button in a tycoon that replaces a model with another model?

I've been trying for a long time to make a tycoon that gradually updates an object through buying something, for example: Buy a wooden door, upgrade to glass door, upgrade to futuristic door, etc.

I took this from a tycoon kit, shortened it and tried to make it at least change the transparency and cancollide, I'm terribly bad at scripting and just starting, but I know I'm missing a lot from this script.

script.Parent.Head.Touched:connect(function(hit)
	local player = game.Players:GetPlayerFromCharacter(hit.Parent)
		script.Parent.Head.Transparency = 0.0
			script.Parent.Head.CanCollide = false
		end
	end
end)		

EDITED Based on TheAlphaStigma's help First: the process this script uses to find the Player from Character doesn't work. Try

player = game.Players:FindFirstChild(hit.Parent.Name)

also 0.0 for transparency isn't necessary, just 0 should be fine. EXTRA: I don't exactly know how this is supposed to work, but consider changing the location of your script to the actual head, and changing your function to:

script.Parent.Touched:connect(function(hit)

If there's still some confusion let me know! If I helped please accept my answer! Thanks!