It really depends exactly what you mean. If you decide to take a more interesting route that is less direct, you can take a detour / take the scenic route. If a road can't be used (because of road works or an accident for example), you can say that traffic was diverted. If you are a bus company and you are changing a bus route, you would just say you are making changes (changing) or amendments (amending). If you want to just suggest another route to a friend, you can just say let's go another way. It really depends on the situation.

detour?

If by "route" you actually mean "direction" (and not "road") then you can say that you want to modify your current route. As for your second sentence you can say that you will head in another direction or eventually take a shortcut (if you found a shorter route to your destination)