Return Flights involves an internal flight

Hi there, I have return flights from London to Shanghai booked, including an internal flight to Beijing. If I don't get a visa in time, can I fly from London to Shanghai, scrap the Beijing flights, and fly return to Hong Kong instead within the 144 hours? And then change onto my return Shanghai flight from Hong Kong on my return. So the flight would be London - Shanghai - Hong Kong - Shanghai - London. Thank you!