Please do not. Changing the supply voltage requires significant redesign of the switching regulator, not merely up-rating some of the components. The frequency and/or duty cycle will change and the magnetics will not be appropriate any more. It will either not work or be a significant fire hazard, even with uprated components. The component ratings required are NOT the supply voltage; some (depending on the switcher topology) need to be rated up to 3x higher, e.g. 600V for use on 240VAC supply.
Originally Posted by PeterB
"Do not meddle in the affairs of wizards for they are subtle and quick to anger". Switching power supplies are well and truly into that territory.