@Saima8 I really don't recommend doing this, especially if the guest has never stayed with you before. The bait-and-switch "upgrade" is a well-known tactic of scammers, some accounts of which have gone viral, and it would look both suspicious and unprofessional if you suggested to your guest that you wouldn't be able to honor a booking for the place he specifically chose - especially if the other property is not even in the same location. I'm sure the 4-bedroom house is very nice, but it might not be an "upgrade" from the perspective of someone who only needs one bed and prefers the location originally chosen.
You could present it to the guest as an opportunity, that you have an opening at a larger home that you could offer at no additional charge, if he would like to stay there instead as a so-called upgrade. But Airbnb doesn't offer a protocol for transferring a booking from one listing to another, so you're still in an awkward spot if he accepts. If he declines, you'll have to either situate your daughter elsewhere or accept the penalties for cancelling the booking.
