If you are still unable to change the name on your system we suggest you to update the Bluetooth drivers of your system and then try again.
So, this is how you can change the Bluetooth Name in your windows 8 or 8.1 machine. If you wish to revert to the default name, click on the default button present in the Advance tab. You can update the Bluetooth name by changing the name under Radio Information. In the Bluetooth adapter properties windows click on Advance tab.