OP may want to reach out to the Corp travel department to find out the specific policies. As others have said, Concur simply implements the policies.

With that said, there are certain things that our travel department can do that Concur can't, even though policies allow it. So for certain trips, usually international, I call in to get specific routings. Although I don't request specific fare classes, as usually we have discounted biz for international and discounted first for domestic positioning legs. I'm just happy to get Delta one, or partner equivalent.