It's easy to revert changes to a file when you've either made a mistake or if you simply don't like the result.
Any edits you make to your document are stored in the History panel. You can then use this, or keyboard shortcuts, to undo an edit. You can also redo an edit which you have recently undone.
Using the panel, if you undo back to a step in history and you continue editing from that step you can reinstate your redo history that would otherwise be lost. This might be because you changed your mind or if you made an edit that accidentally removed your redo history. Two branches in the history are created:
Do one of the following: