Advanced seat selection is now available on all international and domestic flights operated by Vietnam Airlines, enabling passengers to pre-book their preferred seat type and location prior to online check-in opening 24 hours before departure.
The service offers passengers the freedom to customise their travel experience by choosing from extra legroom, forward zone or standard seats in specific locations.
Collected and summarized from the source below by Tran Thi Tan https://www.breakingtravelnews.com/news/article/vietnam-airlines-introduces-advanced-seat-selection/