How do I rename my computer?

I just got a MacBook Pro at an Apple store, and when setting it up tonight, I noticed that Setup Assistant did not appear as it was supposed to. I then noticed that my computer had already been named (I guess by the people at the store?) - my father's last name, not mine, and not what I want my computer to be called.

I changed the administrator preferences and name, but I cannot figure out how to change the name of the computer itself. Thank you for your help!