At 9 a.m. on April 21, 2005, after a few hours of stunting, "Mix 104.1" flipped to "Jack FM." The first song on "Jack" was "Get The Party Started" by P!nk.Radio & Records April 29, 2005 On May 10, 2005, three weeks after the format change, the call letters were officially changed to KZJK.
