It was Gen.musharaf who controlled the army (read whole country and govt ) so don't tell me that a powerless puppet PM went to America by his own to agree a with drawl of troops.. and your army followed his your PM rather than your general. if nawaz was powerless to stop the army from starting a war what makes you think that he could stop the war?
I will tell you what changed, while starting your general was confident of his plan but in execution he failed and got his *** kicked by Indian army.. international pressure was also building up and his all whether friends also didn't move a finger. so musharaf got no option other than withdrawal from remaining areas.