You can apply for a visa extension on your own  or apply through a local agency in Vietnam. Steps to apply are as follows: Prepare the renewal/extension application form NA5 (download it here) a long with your passport. Wait for 5 working days for the result.
How do I renew my business visa?
If you want to extend your stay in the United States, you must file a request with U.S. Citizenship and Immigration Services (USCIS) on the Form I-539, Application to Extend/Change Nonimmigrant Status before your authorized stay expires.
How do I extend my Vietnam visa?
How to extend Vietnam visa
- Step 1: Send us soft copy of your passport and the page containing your current Vietnam visa and we will inform whether your visa can be extended or not.
- Step 2: Send your original passport to our address and pay the extension fee.
Can I renew my visa after it expires?
If you had a US visa which expired, you can apply for US visa renewal. You will receive the same type of US visa again, provided you still fulfil the conditions.
What should I do if my visa expires?
Extension of Stay
If you came to the United States on a nonimmigrant visa and you want to extend your stay you must apply with USCIS before your authorized stay, denoted on your admission stamp or paper Form I-94, expires. It is recommended you apply well in advance of your expiration date.
What happens if I overstay my Vietnam visa?
If you overstay your Vietnam visa for no more than 3 days, you are not required to contact the local Immigration Office, but go to the airport and pay for the fines (about US $23/day ~ VND 500,000), and then obtain an exit visa to leave Vietnam.
How much is a visa extension?
Include payment – The visa extension filing fee is $370 (for you and your family included in the application) but there may be an extra $85 biometric fee involved depending on your current type of visa.
When should you renew visa?
If you want to extend your stay in Canada, you should apply at least 30 days before your status expires. For the steps to apply, see How to apply to extend your stay as a visitor.
How can I renew my visa online?
Complete the Nonimmigrant Visa Electronic Application (DS-160) form. After completing the form, print and save your confirmation page. Register an account on this webpage. Follow the steps to schedule an interview.