When a guest’s payment is declined on a booking request, Vrbo sends you a notification confirming that the initial request has been canceled. A new pre-approval is then sent to the guest so they can attempt to pay again.  

Note: This new pre-approval expires after 72 hours if the guest doesn’t make a payment. 
 
Until the payment has been processed, your calendar is marked as tentative. This means it isn’t blocked and you can accept other bookings during this time.