After you launch a campaign, there are times you may want to make a change. Any time you make a change to the emails or steps in a sequence you should relaunch/apply edits your campaign. Changes are NOT applied to your campaign until this is done.
After you have made the changes you will see this "Apply Edits" button.
This will take you to a page where you are able to review the changes before they are applied. In the bottom right you will need to select "GO LIVE".