How would I choose a power then delete the other?

local debounce = false
local status = game.Workspace.status

status.Value = "Hello"


script.Parent.Parent.SpinButton.MouseButton1Click:Connect(function()

    if not debounce then
        debounce = true
        local debounce = false
    script.Parent.Text = "Spinning!"

    wait(3) local a = math.random(1,3)

if a == 1 then script.Parent.Text = "Chosen skill: Fireball" 

    script.Parent.TextColor3 = Color3.new(255,0,0)


elseif a == 2 then script.Parent.Text = "Chosen skill: Rock" 

    script.Parent.TextColor3 = Color3.new(0,0,255)

elseif a == 3 then script.Parent.Text = "Chosen skill: None" end 





        wait(2)
        debounce = false
    end

end)

This is my script and I want when a player lands on lets say rock for there fireball to be destroyed and the rock to stay how do I do that?