One exemplary embodiment can include an apparatus for transferring catalyst from a regeneration zone to a reaction zone in a hydrocarbon conversion unit. The hydrocarbon conversion unit can include a transfer vessel, and first, second, and third lines. The transfer vessel can transfer regenerated catalyst from the regeneration zone at a first pressure to the reaction zone at a second pressure where the second pressure is greater than the first pressure. Generally, the first line communicates the catalyst to the transfer vessel and is coupled to a first valve to allow catalyst into the transfer vessel and the second line communicates the catalyst from the transfer vessel and is coupled to a second valve to allow catalyst out of the transfer vessel. The third line for allowing the passage of gas therethrough may be at a pressure higher than the first pressure having a first portion communicating with the transfer vessel and having a second portion coupled to third and fourth valves. Each of the third and fourth valves can have a first position that is open and a second position that is closed, which may correspond, respectively, to the opening and closing of the first and second valves to allow gas to pass therethrough.