I discover that you can use Launch in AEM 6.4 to work on a page that you want to publish or promote later in AEM. When i created a Launch option and tried to edit the existing content I noticed that I could not edit or choose the "wrench" icon on any component. Is there a way to edit the exist content on a page once you create a Launch to promote or publish later for a specific date?
You should be able to edit the launch page the same way you edit the content pages.
If the launch is already created, you can select the page for which the launch was created earlier, go to the References option in the left rail and select "Go to the page". This will open the launch page for you. The launches are saved under /content/launches.