1993 Buick Regal Owner's Manual - Page 38

When you sit in a center seating position, you have a lap safety belt, which has no retractor. To make the belt longer, tilt the latch plate and pull it alongthe belt. Buckle, position and release it the same way as the lap part of a lap-shoulder belt. If the belt isn't long enough, see "Safety Belt Extender" at the end of this section. Make surethe release button on the buckle faces upward or outward so you would be able to unbuckle it quickly if you ever had to. To make the belt shorter, pull its freeend as shown until the belt is snug.