Apple Icon > System Preferences.
Computer Name field, enter the new name you'd like to use. Your Mac's Computer Name is also its bluetooth name, as well as its network sharing name. Change this to whatever you'd like you computer's new bluetooth device name to be. The name is saved immediately after changing it -- there is no save button. :)
You can also change the name of your bluetooth devices themselves (headphones, etc.) To do this. return to system preferences, click the
Bluetooth icon, right click a device and select