When running email Cadences, you can select Prospects with different email engagements (for whom the Cadence has been completed) and add them to another Cadence.
Select any Cadence and click on the Prospects tab. Click on the filter and select any Engagement. This will give you a list of all Prospects who match that filter.
Add these Prospect to a new list.
Go to Prospect List and select this list to add to a particular Cadence.