Complex sentence: Northwest WorldPerks was merged into Delta SkyMiles on October 1,2009, operating certificates will be merged by the end of 2009, and reservations systems will be merged by January or February 2010.
Split into simpler sentences: Northwest WorldPerks was merged into Delta SkyMiles on October 1,2009. Operating certificates will be merged by the end of 2009, and reservations systems will be merged by January or February 2010.