Go to the ARTIST CONTENT section of your dashboard and click on INFO & LINKS from the drop down menu.
Once you are on the Info & Links page look on the top left portion of the page under Artist Info. From there you will see in the Artist Name field the current account name, and you'll be able to change or edit the name in that box. Once edited, click OK to save your changes.
You will see that the change has been successfully made when you see the orange "Ok! Saved" message.
And you're done!