Individual sites can be moved after they have been placed. First, navigate to the site that you would like to move and click on the site. This will display the callout box which will contain the Move Site button if your account has proper permissions.
Clicking Move Site will turn the site icon yellow and display arrows on each side. You can the click and drag the site to the desired location. Once you release the click, you will be asked if you want to confirm moving the site. Clicking Yes will move the site to the new location on the map.