2004 Buick Century Owner's Manual - Page 8

Front Seats Manual Seats {CAUTION: You can lose control of the vehicle if you try to adjust a manual driver's seat while the vehicle is moving. The sudden movement could startle and confuse you, or make you push a pedal when you don't want to. Adjust the driver's seat only when the vehicle is not moving. Lift the bar located under the front of the passenger's seat to unlock the seat. Slide the seat to the desired position and release the bar. Try to move the seat to be sure it is locked into place. 1-2