One of the Cybex Gazelle S seat's stopped reclining, what to do?

Hey, Kay,

There's most probably some fault of the internal mechanism. If it's not a simple matter of something being stuck or needing oiling, which, with the seat recline, it most probably isn't (simple visual control of all the moving parts should tell you if it is), then you need to contact the seller or the Cybex customer service as your seat needs repairing or replacing.