Symbols come in a variety of shapes, including the built-in shape options and user-defined symbols.
Customize a toolbox symbol's shape:
In the toolbox, double-click the symbol to change.
In the Symbol Options dialog box, choose the Symbol Shape tab.
Scroll through the Standard Shapes to locate a shape.
Click once on the shape. The Sample Symbol will reflect the selected shape.
Notes:
Any symbols previously placed on the schedule using the old symbol type will be updated to reflect the change made in the Toolbox.