How do you “prompt a lane change or tweak the speed”? Do you say “Hey, Tesla, go faster?”
Does full-auto resume after you somehow make those manual changes?
As of now you can’t use voice commands to control driving. To speed up you either tap the accelerator or use a scroll wheel. The scroll wheel sets the maximum speed higher or lower. It doesn’t directly set a specific speed.
To trigger a lane change just use the directional signal stalk (button on some models) car will safely change lanes. Unfortunately if you want to take another route and lets say make an immediate left an intersection instead of go straight, you have to exit the FSD and do it yourself.
Essentially, when FSD is on, it’s designed to be autonomous and overriding it isn’t always seemless.