The tariffs currently defined are listed in the Tariffs page of the DUAL Softswitch Administrative Control Panel. The table at the top of the page lists all the tariffs, sorted by their name. The final column in this table has a link that allows the tariff to be removed from the system.
All customer accounts must have a tariff assigned to them. The form on the following page asks you to select an existing tariff to be assigned to all accounts that currently use the tariff to be deleted. Select a tariff and press the Continue button. This will remove all references to the tariff from the database and return you to the Tariffs page.