How do you replace keyless remote on a Buick lacrosse?

To replace a keyless remote for a Buick Lacrosse, first, obtain a compatible replacement key fob, either from a dealership or a certified retailer. Next, insert the key into the ignition and turn it to the "On" position without starting the engine. Press and hold the "Lock" and "Unlock" buttons on the new remote simultaneously for about 10 seconds, then release them. Finally, turn the ignition off to complete the programming process.