@Julie74 When you send a pre-approval, the guest has 24 hours to accept in which case the reservation is confirmed. The pre-approval still lingers on past the 24 hours, but if the guests accepts it past that time, it will come back to you for approval.. Here's a link on what Airbnb has to say on Pre-Approvals:
https://www.airbnb.com/help/article/838/what-is-a-pre-approval
So the short answer to your question is no, the guest does not have to send you another inquiry, unless, of course, they want to ask you questions.