Complex sentence: Whilst performing on their first headlining tour, "The Work Tour", the band started to go back into the studio to record their second studio album in early March 2009, which would be due for release in late 2009.
Split into simpler sentences: Whilst performing on their first headlining tour, "The Work Tour", the band started to go back into the recording studio, to record their second studio album in early March 2009. This was so the second studio album would be due for release in late 2009.