Hitler ordered the attack to proceed on 26 August, but upon hearing that the United Kingdom had concluded a formal mutual assistance pact with Poland, and that Italy would maintain neutrality, he decided to delay it.
Hitler demanded that a Polish plenipotentiary immediately travel to Berlin
Wednesday Aug 30, 1939
On 29 August, Hitler demanded that a Polish plenipotentiary immediately travel to Berlin to negotiate the handover of Danzig, and to allow a plebiscite in the Polish Corridor in which the German minority would vote on secession.
The Poles refused to comply with the German demands, and on the night of 30–31 August in a stormy meeting with the British ambassador Neville Henderson, Ribbentrop declared that Germany considered its claims rejected.