For those not familiar, autopilot (auto steering + TACC) is visible via the blue (when active) steering wheel icon top middle right of the dash (see the picture I posted above).
When you get the update, which I assume is starting to roll out to other cars in HK, the notes are very obvious explaining the features and how it works, including auto lane changing.
By the way, I found the auto lane change a bit slow and hesitant for HK roads. I only saw it work once, the other times it took too long and I just took control of the car.