The POD is that the Soviet June 44 summer offensive does less well, the front lines end up settling down 20 miles further east and the Poles don't pull the trigger on their uprising until January 1945.
This time it works, the Germans can't do anything about the uprising, coming right after the Soviets launch their January 1945 offensive and are trying to flee the city.
The home army ends up controlling all of Warsaw, the Government is flown in along with a company of the Polish Parachute Brigade.
Can Poland preserve her independence?