In the parent view of a callout, you can move the leader line to any point on the callout bubble.
If the default location of a callout leader line interferes with other objects in your model, you can relocate it using the following procedure.
To adjust the callout leader line
A blue elbow control displays in the middle of the line.
As you move the control, notice that the leader line attaches to different points on the callout bubble. The leader line segments snap to vertical and horizontal planes.