The chfn command is usefull if you need to change account user info, such as full name or room name. This is also called GECOS, or finger information.
$ chfn -h
Usage: chfn [-f full_name] [-r room_no] [-w work_ph] [-h home_ph]
The chfn command is most used for changing the fullname:
sudo chfn -f "Anakin Skywalker" anakin
Use chfn instead of editing the /etc/passwd file by hand. If you need to change other user account info, use chsh and usermod.