Normally when you move one Bezier tangent handle, the other moves in the opposite direction. You can break tangent handles so that you can adjust each tangent independently and create abrupt changes in your animation.

To break a tangent handle:

1. In Edit mode, select the keyframes you want to break. You can also click AllPts to select all keyframes.

   
   

   (a) Break mode button  (b) Return mode button  (c) AllPts button  

2. Enable Break.
3. If you want to break the tangents for more than one keyframe, disable Return.

   If Return mode is enabled, you are returned to Edit mode after performing one break operation.

4. In the Animation Curves window, click and drag the selected Bezier handle you want to break.
5. If Return mode is disabled, click additional keyframes to break the tangent handles and modify them as needed.