Yes, you can still get alterations done, but it's best to look for a tailor or seamstress rather than taking it to a dry cleaner that does alterations if it's more complicated than hemming pants (and sometimes, even if it's just hemming pants, grr). In SF, Victoria in Lower Nob is great. Taking material out of the shoulders and upper back doesn't look like it'd be difficult, but letting out the waist may be a problem; check the seam on the inside and see how much fabric there is. If the seam allowance is too small, you can't let it out, and that's often the case with clothes these days.