Below is a video guide on this feature:
This feature will hold the trip for 24 hours. For some fares or for trips booked on short notice the airline might require the ticket the same day as booking. In this case the trip can't be held for 24 hours and will need to be confirmed the same day.
Before you place the trip on hold you can see the latest ticketing date under 'Show Details'
******NOTE****** Even though these are very rare cases but as long as the trip is still on hold and no ticket has been issued the airline is allowed to take back the seat at any time without notice**************