How to make a sub-category a Category in Quicken Mac?

Open the Categories window (menu Window > Categories). Grab the subcategory and drag it out between any two top level categories. A line will appear to indicate you've got the right place. Drop it there and it will become a top level category.

By "doing it manually", I'm assuming you mean changing each transaction one at a time. The above procedure will change it everywhere with one action and you will see the results reflected in all your transactions.