Is there a way to offer a guest the opportunity to check in a day earlier if I have an open day before their scheduled check in? It seems like when I did it in the past Airbnb charges them a fee.
The guest can change the reservation with the "change"option" to add the extra night (and pay for it).
Airbnb will add their fee + taxes (if applicable) to it.
Or you can use the change option, add the extra night for free (by clicking in the pricefield and change new calculated price back to the original price). Then no fee will be added, but maybe taxes (If applicable)