   # to clear an actor gate
   #
   delete "/flags/:name/actors/:actor_id" do
-    flag_name = String.to_atom(name)
+    flag_name = String.to_existing_atom(name)
     actor = %SimpleActor{id: actor_id}
 
     FunWithFlags.clear(flag_name, for_actor: actor)

  #
  delete "/flags/:name" do
    name
    |> String.to_atom()
    |> FunWithFlags.clear()

    redirect_to conn, "/flags"

  #
  patch "/flags/:name/actors/:actor_id" do
    enabled = Utils.parse_bool(conn.params["enabled"])
    flag_name = String.to_existing_atom(name)
    actor = %SimpleActor{id: actor_id}

    if enabled do
