The Smart lists area is where you can view, edit, duplicate, reorder, share, and remove smart lists from your contacts area. You can do the following from here:
Reorder - Using the grey hamburger menu on the far left, you can click and drag your smart lists, changing the order in which they display in your contact menu.
Duplicate - Using the clone button, you can create a duplicate of your Smart List, copying the existing filters of the original.
Share - Using the blue hamburger menu on the far right, you can select which users the Smart List is shared with.
Edit - Using the pencil icon, you can edit the name of the smart list.
To make edits to the filter, navigate back to the Smart Lists tab, select the smart list you want to edit, then select more filters. From here, edit your filters and click save.
Delete - Using the trash can icon, remove filters that have been created.