You need hoist mast in a secure way, disconnect quick connect hoses with special forks or with two basic - screwdrivers, then there is the matter of releasing tilt cylindets from mast. After that you may need to also release reach cylinders, but I'm not 100% sure. Last step is to release the big mast axle on both sides of the mast on which the mast usually tilts, it's fixed with hexagon bolts and you may need a large allen key or allen socket. This is also important to rotate the mast axles as they are not 100% round and can be in way of lowering the mast by turning them like 90 degrees it should be ok. All this is done by trained tech in under 1.5h