1988 Cadillac Deville Wiper arm

Is there a holddown nut on the pivot(under a cap?). If not, there is a little slide lock, evidenced by a little tab sticking up on one side or the other. Lift the arm about midway between as high as it goes, and the contact of the windshield, and this tab should slide outward a bit, and the arm should come off. If it has a pivot nut, remove and work it a bit, and it will come off the splines.