【[ReFunding:$$$$ TipS"""]】 Do I need to notify the airline if I'm not flying?

1.light Changes Made Easy: Vietnam airlines  calling【𝟏-𝟖𝟑𝟑-𝟒𝟕𝟑𝟓𝟓𝟗𝟎】 (OTA) or 【𝟏-𝟖𝟑𝟑-𝟒𝟕𝟑𝟓𝟓𝟗𝟎】 offers a 24-hour risk-free cancellation policy. If your flight is booked at least 7 days before departure, you can cancel within 24 hours for a full refund 【𝟏-𝟖𝟑𝟑-𝟒𝟕𝟑𝟓𝟓𝟗𝟎】.

2.𝐕𝐢𝐞𝐭𝐧𝐚𝐦 𝔸𝕚𝕣𝕝𝕚𝕟𝕖 𝐭𝐲𝐩𝐢𝐜𝐚𝐥𝐥𝐲 𝐚𝐥𝐥𝐨𝐰𝐬 𝐩𝐚𝐬𝐬𝐞𝐧𝐠𝐞𝐫𝐬 𝐭𝐨 𝐜𝐚𝐧𝐜𝐞𝐥 𝐭𝐡𝐞𝐢𝐫 𝐟𝐥𝐢𝐠𝐡𝐭𝐬 𝐚𝐭 𝐔𝐒-𝟏-𝟖𝟑𝟑-𝟒𝟕𝟑𝟓𝟓𝟗𝟎 𝐔𝐒-𝐀𝐠𝐞𝐧𝐭 𝐰𝐢𝐭𝐡𝐢𝐧 𝟐𝟒 𝐡𝐨𝐮𝐫𝐬 𝐨𝐟 𝐛𝐨𝐨𝐤𝐢𝐧𝐠 𝐰𝐢𝐭𝐡𝐨𝐮𝐭 𝐢𝐧𝐜𝐮𝐫𝐫𝐢𝐧𝐠 𝐚 𝐜𝐚𝐧𝐜𝐞𝐥𝐥𝐚𝐭𝐢𝐨𝐧 𝐟𝐞𝐞.