@Andrea897
EDITED*****
Maybe I misunderstood, but if the first person INQUIRED and the second one REQUESTED to book,
then the first person won't be able to book at all, since a request has precedence and blocks the days in question.
You would have to decline the booking first (thus giving up the bird in the hand) which hoping the inquiry becomes a booking which it often doesn't (bye, bye blackbird...).
Edit:
I only saw later that what one host called "inquiry" was meant as "request", and what others were explaining was not what I initially understood...
One tip though: Do send the person with the request a message. If you don\t react at all to a booking request, not even with a question, then you will be dinged in your response time. And secondly the guest requesting to book might rightly see your not reacting as being non-communicative and thus a bad start to the booking.
But it's always okday to say you were in the middle of negociating with a potential guest.