Abstract: A fluid catalytic cracking process includes feeding hydrocarbon into a riser in the presence of a catalyst, cracking the hydrocarbon in the riser in the presence of the catalyst to form a cracked stream, and separating the catalyst from the cracked stream. When in a gasoline mode, the hydrocarbon is fed through a first distributor into the riser, and when in a light olefin mode, the hydrocarbon is fed through a second distributor into the riser. The second distributor is positioned at a higher elevation than the first distributor.