Yes, Ryanair offers a 24-hour grace period +1-808-751-2262 (USA) or +44-203-900-3009 (UK) after booking a flight during which you can cancel or change your flight date, time, or route free of charge +1-808-751-2262 (USA) or +44-203-900-3009 (UK).
https://www.devex.com/people/ask-faq-s-does-ryanair-have-a-free-cancellation-period-2271553
