This option makes it so that when someone books your calendar, it is not added to your calendar straight away, but instead you have to either accept or reject the booking. This can be useful if you want to get context from users about meetings and decide if their needs should be best served with a call or not. You can accept or reject the booking from within the bookings page, where you can also view the information and notes from the booking request. When enabled, the user gets a message and an email explaining that you still need to accept or reject the booking, and you also receive an action email asking you to make a decision. Cal.com will send reminder emails if you do not accept or reject a booking.