You will probably never have to delete a team from the DI Scoring Program. If a team withdraws from the tournament or doesn't show up, it is customary to change the team's status. In this way, you retain a record of the team's registration, but remove them from the scoring process. However, if you need to delete a team, you can.
When your changes are complete and saved, refresh the team lists to update all windows. In the tournament window, from the View menu, click Refresh Team Lists.