It is possible to delete a highlight, a note, or a note and highlight.
Removing a highlight:
Tap on the highlighted text in the book and tap "Delete" on the pop-up. Your highlight will be deleted.
Removing a note:
-Tap on the highlighted text with an associated note in the book
-Tap edit note to bring up the Notebook
-Tap Cancel to hide the keyboard
-Tap More in the lower right hand corner
-Tap Clear Note to remove the text
-To return back to the book, tap on the X in the upper left hand corner
Removing a note and highlight:
Tap on the highlighted text with an associated note in the book and tap Delete. A pop-up will appear asking to confirm deleting the highlight and associated note. Tap Delete Highlight to delete the highlight and note.