Complex sentence: It was reformed on 7 January 2000 to take control of air transport, air-to-air refuelling and airborne early warning within the RAF, and on 1 April 2006 it took over the responsibilities of No.3 Group RAF, which was disbanded.
Split into simpler sentences: It was reformed on 7 January 2000 to take control of air transport, air-to-air refuelling and airborne early warning within the RAF. On 1 April 2006 it took over the responsibilities of No.3 Group RAF, which was disbanded.