Replace Annotation/Comment Anchor Content while keeping the Annotation

I’d like to be able to replace the content of a Writer Annotation/Comment anchor. From my experiments doing the following does replace the anchor content, but also destroys the annotation, which I would like to keep intact.

oCurs = annotation.Anchor
oText = oCurs.getText()
oText.insertTextContent(oCurs, newContent, True)

Is there any way to do this?