Needed to change to an earlier flight so I can take an urgent call, however the original connection time was less than the allowed MCT. I was in touch with the Concierge in flight, so in the event that the previous flight arrives early, I can be switched to the earlier flight. About 1 hour prior to landing, we confirmed that we will be about 15 mins ahead of schedule, the Concierge switched my flights. My previous flight pulled up to the gate next to the new flight, basically walked off that flight, and onto the next flight.