Short Answer: rotate the mass/energy distribution that creates the bubble
Long Answer: caution contains science
Alcubierre drives are a really cool, because it moves in a different way to ordinary space transport systems, which move the ship by "throwing" stuff in the direction opposite to were you want to go.
Alcubierre drives instead move by using matter and energy to distort space and time, which distorts the path an object takes through space. Normally if there wasn't any distortion the object would keep moving in what ever direction and speed it started with. But the Alcubierre drive distorts the path of the object so it so that any thing inside the bubble moves with the bubble.
The bubble is created by placing negative energy around it in a specific way, and if energy is arranged in this way you create a bubble, traveling in a direction specified by the arrangement of the energy. so if you rotate the arrangement of energy the bubble will now travel in that direction, dragging its contents with it. An added befit is that it is an inertialess drive meaning that objects contained within don't experience a force either speeding up of slowing down, or turning meaning that the contents isn't pushed to the edge of the bubble.
hopefully that helps