The header (6) comprises at least one support and transport wheel assembly (11,12) comprising an axle (13) and two wheels (14a,14b). The wheel assembly is coupled to the main body of the header (6) by an actuating system (15) that comprises two actuator mechanisms. When changing from the field mode to the transport mode, the first actuator mechanism brings the wheel assembly forward from a position behind the header, after the header has been lifted up from the ground. After completion of this first movement, a second actuator mechanism swivels the wheel assembly to a position that is transversal to the header, after which the header is lowered to the ground. The two-step approach enables the changeover between field mode and transport mode without pivoting or otherwise moving the header (6) relative to the feeder (4). The wheel axle (13) may be pivotably suspended from a frame element (35) that executes the swivelling movement.
