https://www.devex.com/people/cancel-a-flight-with-singapore-airlines-2172600  

𝒟elta Airlines provides a 24-hour cancellation policy 【+𝟣-𝟪𝟧𝟧-𝟩𝟥𝟪-𝟦𝟣𝟫𝟪】. If you book a flight at least seven days before departure and cancel within 24 hours of booking 【+𝟣-𝟪𝟧𝟧-𝟩𝟥𝟪-𝟦𝟣𝟫𝟪】 (𝙾𝚃𝙰)】), you are eligible for a full refund without any cancellation fees. What is the cancellation policy on 𝒟elta? 𝒟elta 𝔸𝕚𝕣𝕝𝕚𝕟𝕖 typically allows passengers to cancel their flights at US-+𝟣-𝟪𝟧𝟧-𝟩𝟥𝟪-𝟦𝟣𝟫𝟪 US-Agent within 24 hours of booking without incurring a cancellation fee, visit or email provided the tick...

https://www.devex.com/people/ask-every-question-what-is-the-a-policy-of-airlines-2172598