I asked them but they say they don't do this for flight. There is still flight available, I can book at the last minute. I can try by land and of rejected try to come back by flight. Would paying the officer a fee be a possibility? With explanation given.
Also the agency may have option but the tourist visa look quite shady, I don't understand how they would do this, at worse I can do this and then go to Savannaket to get a non O, with proof of fund and everything. Agency said it would cost me 2500 on the top of the 4000 for the trip. Tomorrow I will see their answer and could ask another agency too, maybe they have better contact at the border.