Originally Posted by
xliioper
How many passengers are on the same PNR? Note that DL only allows one companion to be upgraded to C+ or FC. If you have more than one companion on the same PNR with you, the system will inhibit anyone from being upgraded. If you split it so that only you and one companion are on the same PNR, you will both be eligible for C+/FC upgrades (at your upgrade priority level).
The trade-off is that the non-Medallion passengers on the other PNR no longer get your medallion benefits as they would if on your PNR. Some of this you can override: check-in agent will generally provide the other passengers with better baggage allowance. Sometimes you can manage SkyPriority security line by just showing one BP for the whole group. One thing that you definitely lose is SP bag tags. They'll only do it for passengers on the Medallion member's PNR. You can try and manage this by checking more bags (up to allowance) on Medallion and Medallion-companion PNR. But only those who have checked bags are eligible for Bags on Time miles award. So if all bags are late, only some passengers in the party can seek the bonus. Again, a bunch of trade-offs.