Annotations can be removed at any time.
To use the Eraser, choose Tool Eraser. The cursor turns into an eraser symbol. Using the Eraser tool, you can remove annotations by clicking them.
Under Tool Tool Styles, you can switch between Whole Annotation/Stroke and Split Strokes. The default mode Whole Annotation/Stroke always erases a whole annotation or whole stokes created with the pen or marker tool. The Split Strokes mode only acts on annotations created with pen or marker tools, and will only erase those parts of the strokes directly below the eraser. This mode behaves more like a real eraser. You can select between different Eraser Widths for this mode.
As an alternative to erasing, you can also select an annotation and then use the DEL key or choose Edit Delete on the menu to delete an item.
Choosing Edit Remove All Annotations causes all annotations to be irrevocably removed from the document.