If your booking request hasn't been approved yet, you can withdraw it and submit a new one without an add-on. If you need to remove an add-on from a confirmed booking, follow these steps:
Contact the host through the message chat and ask the host to remove the add-on from your booking on their end.
Look out for a notification: Once the host has sent you new booking details, you will be notified in-app and via email and will just need to review them and, if everything looks good, approve the changes.
Once you approve the modification, you will be refunded based on the new booking details.