Please review the operators manual for instructions on how to release the transmission so that you can roll the unit by hand.
If this is a tractor style with a hydrostatic transmission, there is a single lever that allows you to activate the dump valve, thereby allowing you to push the tractor.
If this is a "Z200" style mower with hydrostatic drive system there will be two releases that will need to be activated before you will be able to roll the unit.
If this is a "Z400" Style mower with hydrostatic drive system when pushing or pulling the mower, engage the bypass levers. The bypass levers are located at the front of each transmission. Lower the deck if needed. Move the steering controls inward out of the park brake position. Lift the seat. Rotate each bypass lever to the horizontal position. Lower the seat. Push the mower using the sturdy feature of the mower's structure. Do not push the mower with the control levers. To reengage the transmission, rotate the bypass levers to the vertical position.
If this is a "Z500" Style mower with hydrostatic drive system when pushing or pulling the mower, engage the bypass valve on each transaxle. Access to the valves is from the lower rear of the unit. the bypass valves are located on the front, inner sides of the transaxles. Set the deck to the lowest position when accessing the pump valves. To disengage each pump, turn the slot on the pump valve 45O clockwise from the RUN position to the BYPASS position.
NEVER attempt to TOW the unit, major transmission damage will occur.