When you first login to your account you will be brought the the My Teams tab. Here you will see a list of the teams you are associated with. From this list you can remove a team from your account. Click the check box to the left of the team and then click remove.
** When you remove a team from your account it will only remove you from having any further access to the team account. Be sure that there is another admin or head coach associated with the team so that they can access the team account after you have been removed.