Applying for Vietnam visa on arrival from Hong Kong HK

Do I need to apply for a new Vietnam visa

Please help. Urgent! I have got my approval letter for arrival on October 11, 2015. But my plan changed and I need to enter Vietnam on October 8. Can I use this approval letter?

Dear May,

We are sorry to say that you cannot use this approval letter if you enter Vietnam earlier than its arrival date. In this case, you will need to apply for a new approval letter (please click here:

Wish you a happy travel in Vietnam.

Kind regards,