Complex sentence: In 2006 the group released the album "Circles" with Kevin Chalfant (ex-member of 707 and The Storm) handling the lead vocals, but since Chalfant was unable to commit to touring, he was replaced in 2007 by Ronnie Platt.
Split into simpler sentences: In 2006 the group released the album "Circles" with Kevin Chalfant (ex-member of 707 and The Storm) handling the lead vocals. But since Chalfant was unable to commit to touring, he was replaced in 2007 by Ronnie Platt.