After you create a diagram, you can add and remove shapes and edit its text by making changes in the text pane. If you scroll the document while the text pane is open, the text pane remains visible so that you can easily copy text from the document into the text pane rather than retyping it.
You can also customize a diagram by using the options on the SmartArt Tools contextual tabs. You can make changes such as the following by using the buttons on the Design contextual tab:
Switch to a different layout of the same type or of a different type.
If you have entered more text than will fit in the new layout, the text is not shown, but it is retained so that you don’t have to retype it if you switch the layout again.
Add shading ...