I asked this same question a while back. IIRC, you need to log out and then log back in and create a new account.
You could go to your "My Account" and select "Edit my billing and shipping addresses" and then change your name.
I did this once (changed my name to my initials - not very creative on my part) and then forgot to change it back when I placed an order. I think BPL caught it because it had my initials on the package instead of my name - probably caused them to waste a label and forced them to print another one - i don't know??? IIRC, they changed it back for me is all I can figure, or maybe my wife did (???) - she was for a very short time, like 2days or so, interested in what I was doing online.
Don't forget to change it back before ordering gear from BPL. Your mail carrier or post offic might give you a funny look when you go to pick up mail for "tarbubble" - plus can you furnish any I.D. with the "tarbubble" name on it to claim packages? [maybe you could???]