You can snooze your listings, and when the last guest leaves, you can deactivate them. Snoozing will remove the listings from all search results. However, guests will still be able to book if they were to access your listings’ URLs directly.
Alternatively, you can delist your listings. That both removes the listings from the search results, and prevents guests from booking.
Either way, upcoming guests are unaffected, and you can just let them run their course.
You can find these options, as well as a couple of others, under “Listing status”.