You can always write a helper function and import that:

def send_update(%Phoenix.LiveView.Socket{assigns: %{myself: cid}}, assigns) do
  Phoenix.LiveView.send_update(cid, assigns)
end

Your example is also a bit contrived, since you could just assign the value directly. Also note that send_update is asynchronous. It sends a message to the LiveView process, which invokes the update callback as soon as it handles the message. If your code relies on some data wrangling update/2 does, you can just directly call update instead:

@impl true
def handle_event("update_title", %{"title" => title} = _params, socket) do
  {:ok, updated_socket} = update([title: title], socket)

  {:noreply, updated_socket}
end