Delta Air Lines Inc., in one of the final steps of its merger with Northwest Airlines Corp., has integrated the two  carriers’ reservation systems and retired the Northwest Web site, www.nwa.com.

Passengers who booked flights on Northwest now have identical reservations on Delta. They can use the original confirmation numbers and manage itineraries on www.delta.com, according to a Delta news release.

The last regularly scheduled Northwest flight, NW2470, left Los Angeles International Airport for Las Vegas Jan. 30 at 8:45 p.m., the news release said. On Jan. 31, customers who went to the Northwest Web site were redirected to www.delta.com.