To view your ladders, click the People menu and select Ladders. Here you can view a list if your group's ladders that contains the title, status (draft, active, paused, closed, or stopped), when it was created, when it was modified, a statistics button to view overall ladder statistics (number of activists exited and number currently waiting), a hide button to hide the ladder from your view, and a duplicate button. At the top of the page, you can filter ladders by status.
Duplicating a ladder will make a copy of all of its steps and put the new copy into draft, so it can be further edited. In this way you can make changes to an existing, published ladder despite the editing restrictions after a ladder is published. You'd copy the active ladder, edit it and make your changes, publish the new ladder, and set the old one to closed so no new activists enter it and new activists only enter the new, active one.