The Account Owner can change your Team's name or URL through the Team Setting gear in your Account Dropdown menu. Go to the General Settings section.
Change Team Name
Changing your Team Name takes into effect instantly and will be seen by all team members and Guests within the account. Changing your Team Name will not change your Team Url.
Change Team URL
Changing your Team URL will automatically update projects with new URLs. Members and Guests of the account will receive an email with the account's new URL.
For reference, your team url will be read as (yourURL).nifty.pm from within the web application.