Plow that swivels??
Cycle Country makes a release assy (works kinda like an automotive hood release) for $56. I have then attached a rope to each end of the blade (about 12" from each end). The other end of the rope is secured to the rear of the front rack, with enough slack to allow for when the blade catches an obstruction that causes the blade to drop down forwards. For blade angling, pull release, and pull the appropriate rope. Inexpensive, and works fairly well.