Is there a grace period for British Airways cancellation?

Yes, British Airways offers a 24-hour grace period for flight{{𝟏𝟖6️6𝟳𝟯𝟴𝟬𝟲𝟮𝟮 (USA) 𝐎𝐑 +44 𝟴𝟬𝟬𝟬𝟱𝟭𝟲𝟳𝟯𝟱(UK) }) cancellations, meaning you can cancel your booking and receive a full refund{{𝟏𝟖6️6𝟳𝟯𝟴𝟬𝟲𝟮𝟮 (USA) 𝐎𝐑 +44 𝟴𝟬𝟬𝟬𝟱𝟭𝟲𝟳𝟯𝟱(UK) }) within 24 hours of making the reservation; this applies to most bookings made directly with British Airways{{𝟏𝟖6️6𝟳𝟯𝟴𝟬𝟲𝟮𝟮 (USA) 𝐎𝐑 +44 𝟴𝟬𝟬𝟬𝟱𝟭𝟲𝟳𝟯𝟱(UK) }).

𝐁𝐫𝐢𝐭𝐢𝐬𝐡 𝐀𝐢𝐫𝐰𝐚𝐲𝐬 𝐨𝐟𝐟𝐞𝐫𝐬 𝐚 𝐠𝐞𝐧𝐞𝐫𝐚𝐥 𝟐𝟒-𝐡𝐨𝐮𝐫 𝐜𝐚𝐧𝐜𝐞𝐥𝐥𝐚𝐭𝐢𝐨𝐧{{𝟏𝟖6️6𝟳𝟯𝟴𝟬𝟲𝟮𝟮 (USA) 𝐎𝐑 +44 𝟴𝟬𝟬𝟬𝟱𝟭𝟲𝟳𝟯𝟱(UK) })  𝐩𝐨𝐥𝐢𝐜𝐲. 𝐦𝐞𝐚𝐧𝐬 𝐲𝐨𝐮 𝐜𝐚𝐧 𝐜𝐚𝐧𝐜𝐞𝐥 𝐦𝐨𝐬𝐭 𝐫𝐞𝐬𝐞𝐫𝐯𝐚𝐭𝐢𝐨𝐧𝐬 𝐰𝐢𝐭𝐡𝐢𝐧 𝟐𝟒 𝐡𝐨𝐮𝐫𝐬 𝐨𝐟 𝐦𝐚𝐤𝐢𝐧𝐠 𝐭𝐡𝐞𝐦 𝐚𝐧𝐝 𝐠𝐞𝐭 𝐚 𝐟𝐮𝐥𝐥 𝐫𝐞𝐟𝐮𝐧𝐝, 𝐂𝐚𝐥𝐥 {{𝟏𝟖6️6𝟳𝟯𝟴𝟬𝟲𝟮𝟮 (USA) 𝐎𝐑 +44 𝟴𝟬𝟬𝟬𝟱𝟭𝟲𝟳𝟯𝟱(UK) }) , 𝐚𝐬 𝐥𝐨𝐧𝐠 𝐚𝐬 𝐲𝐨𝐮𝐫 𝐭𝐫𝐚𝐯𝐞𝐥 𝐝𝐚𝐭𝐞 𝐢𝐬 𝐚𝐭 𝐥𝐞𝐚𝐬𝐭 𝐨𝐧𝐞 𝐰𝐞𝐞𝐤 𝐚𝐰𝐚𝐲.