Beware that I had to fly out and and back in after ninety days had expired. A seemingly reputable Visa Agent in Saigon told me so, said I cold not do it at the local border. He said you can't renew it at the border, but another said I could???. While here I had to get a new Passport and the frequently asked questions page on the US Embassy Website states that to get your current visa into your new passport to go to one of two locations which they listed. Me and another guy went there who I met at the US Consulate together and they told us to screw off go see a Visa Agent. I called one and they wanted 290usd for this service. Now totally confused I went to the airport and the guy there said I could stay till the remaining days out of the current 90 then I had to leave. I was also told by another agent that I could fly out with both passports and then only return for one month before having to leave the country to get a new visa. Total confusion. Has anyone dealt with anything like this?

The locations where they tell you are Vietnam immigration stations