Click on the Actions button for the article and select Edit from the menu.
The article appears in Edit mode. In this screen you can edit anything in the article except for the article ID, which can not be changed once the article has been created. You can choose to increment the version every time you edit the article to help all users see how often the article has been changed. If you feel that the changes you are making are very minor, you can choose not to increment it. Note that if you set the expiration date to a date earlier to the current date, you will no longer be able to select that article for use in the Journal Content portlet.
Make necessary changes and click Save.