Welcome to Fluther.
I don’t doubt that such a surgery is at least possible. So, yes, I’m sure “it can be done”. But I doubt whether an ethical surgeon would perform that surgery without a lot of questions – and assurances that you can’t yet deliver, I think – beforehand.
An ethical surgeon would question you – I think (I’m not a surgeon, so I can’t say for certain what they would or should do) – about your reasons for wanting this surgery, and all its attendant risk, for such a relatively minor outcome. After all, a single centimeter over the width of a normal person’s shoulders seems pretty niggling and insignificant. I can certainly understand someone wanting to reduce a centimeter from the length of a nose, for example. That’s right in the middle of your face, and a centimeter there is a lot. Over the width of a normal person, though? The ethical surgeon should counsel you first to “seek counseling” about why you have such a negative and hyper-critical body image that this is a significant thing for you.
So that’s what I would do, too, is to suggest that you speak to a counselor before you speak to a surgeon.