Somehow delta.dumb will not let you pick the fare class you want, so you need to call the elite line or, if not elite, to either call and have them book and hold the ticket for you to be purchased on line or to ask to be put through to IT support, probably in India, since the website will not let you book your ticket.

However, be careful about breaking the fare. This sometimes makes the ticket MUCH more expensive than using the higher class through fare nd getting it's benefits. In fact, delta.dumb will offer connections using different fares when clicking the higher fare or above box on advanced search will give you a low cost ticket on the same flights.