At the Personal Info / You and Your Family summary screen, click the Edit button next to Dependents. On the next screen, click the Delete button next to the dependent you want to remove.
If you want to remove a dependent, but save his info, in case you may asdd him later, click the Edit button instead of Delete. Go through the interview and let TurboTax disqualify him as a dependent. That will save his dependent info worksheet but delete him from your actual tax forms.
