Change from single to multiple entry

Question:

I put in my application for 3 single entry visa’s last night, but my travel companion has come to me this morning asking if she might be able to change to a multiple entry. Is it too late to do this.

Answer:

Dear Smith

We have checked your application and we are afraid that it is now too late to change anything on your application. However, you can still use the single entry visa and apply for another one when you leave Vietnam.

We are sorry for any inconvenience caused.