By default, you can drag-and-drop items in your subscriptions tree hierarchy to move a folder from one place to another. Here is another way to do the same job:

Alternative Way:

Or you can use following procedure:

• Open context menu of that subscription or folder
• Select 'Move' menu option, which will open a dialog to select that folder
• Then select the folder you like to move that folder under
• Click on 'OK' button to finish the process