What you mean by alter? Wheels/rims can't be altered and it's not safe.
or the issue you have with bolt pattren? If yes you can use hub adapter to change to required pattren.
Or you want to fit 17 on a car with stock 15" or any other? . you might need to work on suspension as well.
Tires and wheels are the most important part on the vehicle. Don't do any funny unsafe dangerous upgrade.