You have not provided enough information here. Are u talking about US (48) domestic complimentary upgrades or international upgrades? If US domestic, the reciprocal agreement has not been made yet between DL and CO/NW. So, the answer is NO. If international, there is no such thing as complimentary upgrades unless flight is overbooked and business seats are still left after Delta Elites are upgraded, then u have no chance as the priority is placed amount Skymiles Elites first then SkyTeam Elites.