@عماد-شعبان0
Hello! It is probably best to contact Airbnb support and they can help you determine what you would like to offer.
I had a guest who checked out at 11am then left their luggage here to pick up later and then they asked to rebook at 6pm. I really wished they decided earlier to stay an extra night as I already cleaned the space. I offered them one more night at their average nightly rate and waived the cleaning fee as a courtesy. They greatly appreciated the gesture.
You cannot change or alter a reservation if the check out time has passed though. When one sends a special offer you also must be aware if that price is the nightly price only or if it is the nightly price with the cleaning fee included in the special offer price. For this reason I would just contact support and ask them for help extending the reservation at whatever nightly rate you decide.