Preheat the air fryer: Set the air fryer to 350°F (175°C) and let it preheat for about 2-3 minutes.
Disassemble the burger: Separate the burger patty from the bun. You don't want to heat the bun and patty together because the bun may burn before the patty gets fully warmed.
Place the patty in the air fryer: Put the patty in the air fryer basket. Avoid stacking other items on it to ensure even reheating.
Reheat the patty: Cook for about 3-4 minutes, flipping it halfway through to ensure even heating.
Warm the bun: In the last 1-2 minutes, place the bun (without any sauces) in the air fryer to get it warm and slightly crispy.
Check for doneness: Ensure the patty is warm enough (you can cook it for an additional minute or two if needed).
Reassemble the burger: Once everything is warm, put the burger back together with the condiments and enjoy!