If you are loading at max, I'd drop down a bit on the powder charge with the new brass and work back up. But, if you are shooting a moderate load, I'd just load em and shoot em. That's if you are a hunter. If, however, you are a long range shooter into extreme accuracy, I expect they would do a new load work up.
I've switched to Norma and Lapua on most of my brass, and I normally go with the powder charge I've been using. Accuracy has not suffered, but I'm not shooting at long distance.