Myriad techniques exist to reduce shoulder dislocations, which includes scapular rotation, Hennepin, Snowbird, Cunningham, and Legg maneuvers. They are nicely reviewed at ShoulderDoc.co.uk. You can also supplement any technique with ultrasound-guided intraarticular lidocaine for improved pain control.
Recently, Dr. Jay Park (Beth Israel Medical Center in New York) contacted me about his novel approach to shoulder reduction which anatomically makes sense. If his animation video doesn’t convince you, check out the video of an actual reduction.