You can either update a Candidate’s CV or replace the existing CV of the candidate by uploading an updated CV.
To edit a Public or Private CV
Select View Document by clicking the Private CV or Public CV icon in the toolbar of the Candidate Record. This opens the private CV or public CV in Microsoft Word.
You can edit the text here and then click File > Save to update the CV and then close the document. This gets updated in the Candidate Record when you click the Save icon in the toolbar.
To rewrite your Public or Private CV
If you have updated lot of content in your CV and you need to replace the existing CV, you can select Upload New Document by clicking the Private CV or Public CV icon in the toolbar of the Candidate Record. You will get the following window where you can use the Public tab or Private tab to browse for your new public or private CV respectively. Then click Upload to replace the existing CV.
You can also see here for more information.