@Frances40,
If it is an inquiry (not a request !), then there is a button "special offer" when you are looking at her inbox.
Just click it and sent her to offer. If it is a request, she must withdraw it first before the "special offer" button is there. If nothing helps, you can accept the reservation as "normal" and change the price via the "change reservation" option OR change the price in the calender for the specific dates or create a custom discount for the specific dates, before she books.
But the "special offer" is by far the best and easiest way to manage this !
Best regards,
Emiel