Changing the battery in a key fob is usually straightforward. Most key fobs have a small slot where you can use a flat tool to gently open it. Once opened, you can replace the old battery with a new one, typically a button cell like CR2032. Make sure to align the battery correctly according to the positive and negative signs. Have you ever changed a key fob battery before, or is this your first time trying it? Let me know if you need more specific guidance for your car model!