The only reason to reduce development if you overexpose film is if you've overexposed so much that the highlights will block up on the shoulder of the film's curve. That won't happen with most modern films until you've overexposed 3-4 stops (or more).
Develop normally. You'll end up with a dense negative and you'll have a longer print exposure time. That's all. If you have really small film or are making a huge enlargement, there will be more grain. That's the price of overexposure.
If you reduce development and then print contrastier, grain will be worse.
FWIW, I've got a couple of (unintentionally) overexposed negatives that print black white when making a proper proof and that make stunning prints. I overexpose 320Tri-X intentionally too at times by a stop or a bit more to get shadow values up onto the straight(er) line portion of the curve. No problems ever developing N or even N+1.
Best,
Doremus