I originally was flying to Vietnam and arriving on the 13th of July, but there have been many delays and I'll now be arriving on the 29th. I received my visa approval for the 13th. Can I use that one when I get there on the 29th? Or do I need to reapply for a new one?
Thanks for your question,
Based on the information that you provide us, your visa had valid from 13th of July so you can use this letter for enter to Vietnam on the 29th normally.
However, You need to check the expiry date of the visa as you have lost 16 days for changing the date of entry.
Ken- Evisa Support Team