An apparatus for accumulating sheet material in a sheet handling system including a first conveyance, a second conveyance, an auxiliary conveyance and a processor to control the conveyances based upon a selected operating mode. The first conveyance receives singulated sheets and conveys the sheets to an accumulator station to produce completed collations. The second conveyance is operative to dispense completed collations from the accumulator station and, receives the completed collations from the first conveyance, in one operating mode, and from the auxiliary conveyance in another operating mode when the first conveyance is inoperative. The processor is responsive to a next collation signal, to control the conveyances based upon a selected one of the operating modes.