REMINDER: You can only leave a group if it's settings allows it. If your group settings is "locked", once first game tips off Thursday March16th , you will NOT be able to leave your group. You can always leave a group prior to tipoff.
To quit a Tournament Challenge group,
Visit your group page and select "Leave Group"
Select the entry you wish to leave the group
If you left the group successfully, you will see a banner that says so.