Actually, pre approvals do NOT hold the space for the guest and preapprovals do NOT tie up the room for 24 hours!! Preapprovals dont' block your calendar, or hold the space for guest. @Jim-and-David0 --- Please dont' give out incorrect information here, you can really throw people off.
See this Airbnb help article for info on preapprovals:
https://www.airbnb.com/help/article/912/what-hosts-need-to-know-about-pre-approvals
WHich is why you can preapprove any number of guests for the same exact dates or overlapping dates. And which is why, after you preapprove someone, if you look at your calendar for those dates, you will not see those dates blocked. Then the first one who books, gets the reservation. It's not preapprovals that block dates -- it's guests booking on the preapproval that blocks the dates. It is good to tell guests that a preapproval does not hold the dates for them, since some think it does, and may be upset to find out that after you preapproved them, someone else jumped in and booked the dates that they wanted.
See this earlier post I did for more clarification:
https://community.airbnb.com/t5/New-to-Hosting/Oops-I-preapproved-two-guests-for-the-same-date-Now-w...