If you don’t want to save changes you made to your document since opening it or last
saving it, you can undo them.
Here are ways to undo changes:
To undo your most recent change, choose Edit > Undo or press Command-Z.
To undo multiple changes, choose Edit > Undo multiple times (or press Command-Z)
multiple times. You can undo any changes you made since opening the document or
reverting to the last saved version.
To undo one or more Edit > Undo operations, choose Edit > Redo (or press Shift-
Command-Z) one or more times.
To undo all changes you made since the last time you saved your document, choose
File > “Revert to Saved” and then click Revert.
To revert to the last saved version after making changes you did not save:
Choose File > “Revert to Saved.” The changes in your open document are undone.