On Facebook, you’ll want to go to your “About” section. Typically, you’ll find this on the lefthand side of your page. Then, you’ll be able to edit the name of your page. Please note: Facebook needs to confirm this change, so you could be waiting up to 48 hours for the change to occur.
http://redvinestudio.com/rebrand-facebook-business-page-without-create-new-page/