airlines will normally prefer to offer affected passengers a re-routing option on their own services or, where applicable, those of their partner airlines. [...] However, in circumstances where there is no re-routing option under Article 8(1)(b) on its own services or, where applicable, on the services of its partner airlines, on the same day as the original flight and via the same route, the CAA’s view is that the airline should next seek to identify rerouting options on the services of alternative airlines on the same day as the original flight and via the same route.