So I recently purchased a new aircraft with a longer range, in order to take advantage of a route without having to do a technical stop. However, I do not want to start this aircraft out at very low load factors if I can help it. Is there a proper technique in which to swap aircraft for a particular route?
Cancel the old route, keep the slots, create the new route.
There's no reason it will start out at very low LFs, assuming you already have the RI at 100. It won't drop because you've changed planes/route numbers.