Complex sentence: He transferred to the University of Cincinnati after his second year to complete his pre-med studies there because the University of Florida had no medical school at the time; but only attended for a year and a half, before he changed his mind about becoming a doctor.
Split into simpler sentences: He transferred to the University of Cincinnati after his second year to complete his pre-med studies there, because the University of Florida had no medical school at the time. However, he only attended for a year and a half, having changed his mind about becoming a doctor.