1. Disarm it remotely by pressing the "Unlock" button on your key fob twice, or put your key in the driver's side door and turn it on and off.
2. Enter the vehicle. Insert the key into the ignition and turn it to the "On" position. This should turn off the alarm.
3. If the alarm does not turn off, press and hold the "Valet" button, which is usually located under the dashboard, for at least 5 seconds. This should disable the alarm.
4. If you still have trouble disabling the alarm, check your vehicle's owner's manual for specific instructions on disabling the alarm.