How to remove the stress from a stressful event

Like anything else, the solution is to practice. Here, the worry is performance pressure, and how that affects the result, so I should practice while I'm under that stress. So for example, I'm freaked out about performing Mozart with an orchestra. Actually, I'm more freaked out about rehearsing it, particularly worried about bombing the first rehearsal. A rather useful piece of advice I got given, from a professional soloist I contacted by email, was to not let that first rehearsal with orchestra be my first public performance, but rather to arrange something else first. Okay, so now I'm going to do it in front of my wife's piano club. This actually makes me pretty nervous, which is a good sign. And now the pianist who's agreed to play the reduction wants a rehearsal. This Friday. I'm now freaked about that. All very good. By the time I'm actually standing in front of an orchestra, I'll have had many opportunities to try and play this piece while freaked out, so hopefully it won't be a problem.