This is what they've said so far regarding that ( a memo from NW SVP Crystal Knotek):
1. In a city where NW has ramp staff (eg. DFW, PDX, SFO), and DL does not, NW will "take over" the handling of both. If there are DL people who have recall rights back down to the ramp, they will be allowed to do so.
2. In a city where NW is totally outsourced, but DL has above wing employees (eg, COS, BDL, OKC), DL will take over both operations, with the ramp to stay outsourced.
3. In a city where NW is mainline, but DL is operated, by a connection carrier (eg. MSN, FNT, GRR), NW will take it all over (above and below wing).