Complex sentence: Things did not go well for Hamburg Airlines and by 1997 it was in dire financial problems, when no buyer or merger partner could be found, Hamburg Airlines was liquidated on 21 December 1997.
Split into simpler sentences: Things did not go well for Hamburg Airlines and by 1997 it was in dire financial problems. When no buyer or merger partner could be found, Hamburg Airlines was liquidated on 21 December 1997.