Originally Posted by MSPeconomist

It's not in the published program rules, but you can SDC on domestic segments that are part of an international itinerary after all of the international segments have been flown.

I've done it either by calling the DM line upon landing or by talking to a DL agent either right after customs (before re-dropping any checked bags) or at airports like LAX upon arrival at TBIT, by keeping my checked luggage and taking it myself to the DL SkyPriority check in area and talking with an agent (or redcoat if the agent doesn't want to allow it) there.