How do you reprogram key for Lexus ES350?

To reprogram a key for a Lexus ES350, first ensure you have a working master key. Insert the master key into the ignition and turn it to the "On" position without starting the engine. Then, turn the key back to the "Off" position and remove it. Within 5 seconds, insert the new key and turn it to the "On" position; this should program the new key. If you encounter issues, consult the owner's manual or visit a dealership for assistance.