@Ellen358 When you put in a reservation request, the host has 24 hours to either Approve or Decline it. If they Decline it, they get penalties from Airbnb in their acceptance rates. When they approve it, Airbnb automatically goes on to charge your credit card (which is why there's that "pending" notice). Those dates are also automatically blocked on the host's calendar, so that no one else can book, which often results in a loss to the host if you withdraw the request and they are then unable to rebook those dates.
So, if you just want to ask the host some questions before committing to a booking, please send the host an "Inquiry" message, rather than a Booking Request. That option doesn't block the host's calendar, they don't have to either approve or decline it, they just have to message you back, your credit card won't be charged, and you won't have to withdraw the request, as Emiel told you how to do.