Complex sentence: On 2001-04-25, the station changed it's call sign to KZNZ, on 2003-02-18 to KMXM, and on 2006-09-20 to the current KXFF.
Split into simpler sentences: On 2001-04-25, the station changed it's call sign to KZNZ. On 2006-09-20 to the current KXFF.