Changing Animation Smoothly

Sometimes, you might need to alter a pose without changing the flow of the animation. To do this:

1. Select a part of the animation on the Timeline.

2. Set the frame indicator to the keyframe that needs changes.

3. Enable Interval Edit Mode:

4. Make sure it is set to Bezier:

5. Now you can edit the pose of your character.

As you can see, changing the pose in one frame affects the neighbouring frames as well. And the closer the frame is to the current frame, the greater is the influence.

The way Interval Edit Mode affects the trajectory is also dependent on what kind of Pivot you are using.
There are two options: Fixed and Moving pivot; each one is useful in specific situaltions.
To learn more about it, see the Pivot section of the Interval Edit Mode page.