Managed Progress Boards are Progress Boards that you can invite other people to interact with whereas basic Progress Boards can only be used by a single Board Admin.
You can neither convert a Managed Progress Board into a basic Progress Board nor convert a basic Progress Board into a Managed Progress Board
They display the Managed title in their sub menu
If you are a Board Admin you will see the Edit Managed Board button in the sub menu
Getting Started with Managed Progress Boards
Use a Managed Progress Board as a Board Colleague
Edit a Managed Progress Board
Archive a Managed Progress Board