Originally Posted by
MSPeconomist
IIRC DL's rules for SDC do say that the new flights must constitute a valid routing and otherwise obey fare rules.
I've had the DM line, and customer support both tell me that routing doesn't need to be per the fare rule. SDC rules override fare rules, and that there's no routing restriction listed in the SDC rules. It's the same reason SDC specifically list E fares as exempt, because otherwise despite the fare rule saying no changes, if the SDC rules didn't say it, then they would be allowed per the SDC rules