Changing your profile name is very easy to do.
At the top of the site, in the menu to the right, is a drop down when logged in.
PROFILE page takes you to all your art as you have set it up
BEHIND THE SCENES is the administration area where all the tools are to set up the site.
At this time you are looking for your CONTACT INFORMATION area. If you just need to use one name, add the name in the first name space and then a space in the surname area.
If you need the URL also changing, just let me know exactly what you want. No capital letters or full stops (.) and must be under 20 characters
If you mean a domain name and not an account name
Go to your artistwebsite premium site
Log in
Go to CUSTOM NAME DOMAIN
Add your website on that page as
yourdomain.com
(or whatever your domain is) with no html or www
then follow the directions on that page
If you get stuck I have a tutorial on my own site http://1stangel.co.uk/fineartamerica/2014/10/25/custom-domains-artist-website/
Hope this helps
Abbie