Yes, you can cancel your Allegiant flight without a penalty if the cancellation is made within 24 hours of booking at +𝟭-𝟴𝟯𝟯_𝟰𝟯𝟵-𝟮𝟲𝟳𝟬 OR +𝟭-𝟴𝟯𝟯_𝟰𝟯𝟵-𝟮𝟲𝟳𝟬 (US) and the flight departs at least seven days later.