Complex sentence: SNCF, the state-owned railway company, has recently introduced a customer fidelity program called "S'Miles", at the same time Air France renamed its frequent flyer program "Fréquence Plus" as "Flying Blue".
Split into simpler sentences: SNCF, the state-owned railway company, has recently introduced a customer fidelity program called "S'Miles". Meanwhile, Air France has renamed its "Fréquence Plus" frequent flyer program "Flying Blue".