What is the process for 121 guys to get a new routing if there is bad weather along the route of flight? Look at your onboard radar and pull out the charts and see what the way around it is, then ask ATC to amend it, or does dispatch generally try to keep an eye out and stay one step ahead of the captain to get a new routing away from the bad stuff? If you get a new routing, do you have to get a new release from dispatch, or only sometimes, say it's a dramatic rerouting that would obviously require more fuel.