When you have a shape, line, or multiple shapes and lines selected you can change their properties at the same time.
To do so, make your selection and in the Design tab click on Fill or Line to see the options available.
For example, let's say you selected your entire organizational chart:
You can change the fill color of the selected shapes and it will apply it to all shapes, leaving the lines alone:
Similarly, if you choose to modify lines, it will only affect the lines connecting the shapes and the border of shapes.
We changed the thickness and color of all the lines.
You can change several properties of your selected items this way including: