SmartDraw's Automatic Shape Connectors automatically draw and adjust lines for you, but you can adjust the spacing of:
To manually adjust a branch, click the connector to select it and a variety of handles appear along the line.

Clicking and dragging the black square
handles at the corners will widen the branch while maintaining even spacing between the symbols.
Click and drag the black square handle or black circle handle on the outermost symbols to change the distance of all the symbols on that level from the horizontal branch.
Click and drag the black square handle in the center of the horizontal branch to change the distance between the upper symbols and the horizontal branch.
Any white diamond-shaped handle
will adjust just one specific segment without keeping the spacing even.