You must duplicate a symbol if you want to modify a copy of it without altering the original symbol and the other copies.
To duplicate a symbol:
|1.||In the Timeline view, go to the frame where you want to duplicate the symbol.|
|2.||Select the symbol's cell.|
|3.||In the top menu, select Edit > Duplicate Selected Symbol.|
In the Library view, the symbol is duplicated and in the Timeline view, the current cell is replaced with the new symbol. You can now modify the symbol's content.
|•||Creating a Symbol|