Six candidates will appear as guest conductors during the Oklahoma City Philharmonic 2016-17 season, and one of them will possibly become the orchestra’s next music director when Joel Levine, the ensemble’s sole music director since its establishment in 1989, will retire in 2018. The candidates are the South American Andres Franco, music director of the Tulsa’s Signature Symphony, the German Alexander Mickelthwate, music director of the Winnipeg Symphony Orchestra, the Brit David Lockington who served music director of the Grand Rapids Symphony in Michigan from 1999 to 2015, the German Andreas Delfs, the American Daniel Hege, music director of the Wichita Symphony in Kansas, the Serb Vladimir Kulenovic, who studied with Kurt Masur and is now music director of the Lake Forest Symphony in Illinois.