My guest and I negotiated a fee and I changed the daily rate. He booked and then the 10% discount was incorrectly applied due to him staying for longer than 7 days.
I want to charge him that discount back however he hasn't paid the reservation in full yet.
You could try discussing it with your guest again but it would have been in your settings to apply the discount to any booking of 7 days or more, You should have removed the discount setting prior to the guest booking, ABNB will not change it , Negotiating and changing daily rates means changing other settings as well. Explaining to guest that a discount was applicable if booking 7 days would have been more appropriate than changing daily settings
@Kerry0 you can not alter the reseveration until it has been completely paid for. Document in the AirBnB messaging system that once the reservation is paid in full you will be requesting X dollars for the difference as agreeded upon. That way you have backup this was agreeded upon before the bill was paid in full and they can not agrue or refuse the alteration to the reseveration money request you send them if they still want the pace. If you have a moderate or flexible they can say no/decline it and you at least have proof it was mutual that they pay this, but they can still cancel and get a refund without a strict policy most of the time.