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:
a visible new branch containing any new edits.
a hidden branch (viewable via a Cycle Futures icon) storing the redo history.
To undo or redo a change:
Do one of the following:
From the Edit menu, click Undo to go back one step, or Redo to redo the step previously undone.
On the History panel, click one of the entries in the list to jump to that step.
On the History panel, drag the slider left to undo a change, right to redo a change.
To return to root:
On the History panel, drag the slider to the farthest position to the left.
To save history with a document:
From the File menu, select Save History With Document.
In the Saving With History dialog, click Yes to accept the conditions discussed in the dialog.