I don't think there's such a thing as "turn off" Format. Format is something which tells Teradata how to display the contents of the column. It Does not effect the way in which the data is stored internally.
Even when you do not explicitly specify a format for the columns when you create a table, TD internally assigns a default format type to the column. This is what is used to display the value when you do a select.
You can however override the default format type of the column by using the FORMAT command.