I believe there is a very serious bug in the web site that produces a blank page, or at least a page missing all the info relevant to this reservation request, when you click on the "Respond" link. Or, on an iPad, the "Respond" link does nothing, no response, not even to give you the blank page. They had better fix this right now, or they will lose a lot of bookings.
The way I worked around it today was this: I used the Airbnb app on my phone to simply Accept the reservation, even though the dates and price were wrong. Then I went to a desktop computer and logged in to the web site, and went to my dashboard and clicked on "My reservations" and then clicked on "Change or cancel" for this one, and set the correct check-in and check-out dates, and the correct price, as this was a special offer. Then when I saved this, the guest was sent the change, and when she approved it, the resetvation became confirmed.
But this was a needlessly complex, roundabout way of achieving the booking, not guest-friendly at all. The guest had to log in twice. This method may fail for a less patient guest. They really need to make it so that I can simply and easily extend a special offer to a guest, including the dates and price, and all they have to do is click "Yes" on it and enter their payment info if they haven't already. That would be far more user-friendly and thus would result in a more successful booking rate.