The magnetic field generated is always perpendicular to the direction of the current and parallel to the solonoid. Hence if we reverse the current the direction of magnetism also reverses. In other words the magnetic poles gets reversed (North pole becomes south pole and the south pole becomes the north pole).
Magnetic field is the volume in which the magnetism of the magnet can be percieved or detected. Hence that doesn't change but the direction of the field definitely reverses.
