This doesn't reload the page, but you can listen for the change and load different forms in Ext, for example
Today, however, I needed to change the URL without adding an item to History, yet still fire the Ext.History.change event. To do that call:
window.location.replace('#somevalue');
I added a function to Ext.History:
Ext.History.replace = function(value){ location.replace('#' + value);
You might want to use this to go from contacts/create to contacts/99 (say it autosaved), without the using having to hit back twice to get back to where they came from.