Complex sentence: However, the negotiations between Gazprom and Naftohaz over a gas prices and a new gas supply agreement failed and on 1 January 2006 Gazprom started reducing the pressure in the pipelines from Russia to Ukraine.
Split into simpler sentences: However, the negotiations between Gazprom and Naftohaz over gas prices and a new gas supply agreement failed. On 1 January 2006 Gazprom started reducing the pressure in the pipelines from Russia to Ukraine.