Complex sentence: Later, Sibo and Mongol battalions were upgraded to regiments, but when Kazakh irregulars under Osman Batur defected to the Kuomintang in 1947, Kazakh cavalry regiment of National Army defected to Osman Batur.
Split into simpler sentences: Later, Sibo and Mongol battalions were upgraded to regiments. When Kazakh irregulars under Osman Batur defected to the Kuomintang in 1947, the Kazakh cavalry regiment of National Army also defected to Osman Batur.