how can i remove main-category from the URL of sub-category in magento

[GumElendume]

hi i have a website in magento which contain url like mydomain/Parent-category/sub-category but i wnat to this URL for sub-category Like mydomain/Subcategory..please help me how can i remove main-category from the URL of sub-category in magento...i will be greatfull...thanks lot... i want URL like http://www.Sofasshopping.com