Can you change offset by machining

[a2lt16v]

Is it possible to get the back of a wheel machined to bring the offset closer to vauxhall. eg can you machine a 35mm of set to like a 45.

Just to bring the wheel in a bit or maybe machine the drums or the front discs or would this be dangerous in regards to the strength side of things

[spanishfly]

You can machine wheels to certain amount, unsure how much??