Ok folks, any seasoned expat here know the best/fastest/cheapest/most efficient way to swap visas? I'm currently on a student X visa and my company *finally* came through with the invitation letter. Already did physical, provided proof of my *expertness level* and green lights all the way. Do I really need to go to HK to change the visa??? Is there any way to do it in mainland? Better yet, has anybody here tried just mailing all the paperwork back to the their home country (for me the USA) and pay an agency just to process it like a new visa then have it mailed back to China?

Best,
Jon