A catalytic distillation packing that has continuous smooth channels over its entire length is used to change out catalyst in a catalyst distillation arrangement without replacement of packing units and long turnaround times. The long, continuous channels are formed from perforated, corrugated plates that have a sufficient thickness to maintain the geometry of the channels and permit free catalyst flow for catalyst change out. The thickness of the plates also eliminates the need for complicated bracing and attachment arrangements that adds to the expense of the packing arrangement and can obstruct the movement of catalyst therethrough. The long, continuous channels are used with an inlet arrangement that provides ready adjustment of the number of channels that are filled with catalyst and channels that are free of catalyst. It is also possible in this arrangement to operate with a channel arrangement wherein all channels are filled with catalyst.