When you click the (m) to move the subcategory, you will see a select box titled "Move Yoursubcat to:"
In that box, select "Top" (at the top of the list) and your subcat will go into Top and become a top category.
When you click the (m) to move the subcategory, you will see a select box titled "Move Yoursubcat to:"
In that box, select "Top" (at the top of the list) and your subcat will go into Top and become a top category.