By clicking a single button, you can undo all transformation edits performed on an object. The reset command will undo all scale, skew, and rotation operations.
Use the Reset button on the Transformations tab of the Object Editor or the Object tab of the Quick Properties Editor to undo an object’s transformations.
OR
Click the Object Editor button: in the Align Bar
OR
Select Object>Object Editor.
The Object Editor dialog box will open.
You can also undo transformations using the Reset button on the Object Tab of the Quick Properties Editor dialog box. Click the button, and then confirm in the message box that you want to reset the object’s transformations.