Comment by rockostrich

>A smart travel agent could in theory use this to cancel an old booking and book again if the price is reduced, but I think some airlines have changed their practice to avoid this.

This is called churn and airlines are pretty on top of it. If you do this often then it will completely ruin your relationship with the airline. Maybe individual travel agencies can get away with it if they're trying to book a handful of tickets each week but OTAs can't.

> I think some airlines have changed their practice to avoid this.

AFAIK even direct connections still use the pattern of creating a PNR, confirming the booking, and then issuing a ticket. Even so in the US, airlines have to guarantee a full refund if a domestic flight is cancelled within 24 hours of booking.