To exchange a symbol instance’s definition with another:
Select the existing symbol instance.
In the Object Info palette, click Replace.
Alternatively, right-click on a symbol, and select Replace from the context menu.
The Choose a Symbol dialog box opens.
Click the symbol selector. From the Resource Selector, double-click a different symbol to apply it.
Select Replace Class to assign the replacement symbol’s class to the replaced symbol; deselect it to retain the original class of the replaced symbol.
Click OK.
The symbol instance is replaced with the selected symbol instance.
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