Airlines' courtesy fare-hold and 24-hour cancel/change policies

Need to "think about it" before buying an airfare so you can shop around? Or make a mistake in your booking and need to make a change or cancel altogether? Most airlines have a 24-hour fee-free change/cancellation policy, but there are subtle differences, as the chart below explains.

Airline	Cancellation/change with or by	How to cancel	Notes
Airtran	4 hours	by phone	voucher for future travel
Alaska	24 hours	phone/online	fare must be paid for to hold
American	24 hours	phone/online	fare does not have to be paid for to hold
Continental	24 hours	phone/online	fare must be paid for to hold
Delta	You may cancel and refund your ticket in full until midnight, one day after the reservation is made. For example, a ticket for travel originating in the United States purchased anytime on Monday can be cancelled and refunded until midnight on Tuesday. If the reservation is made on the date of travel, you may cancel and refund your paid ticket in full until midnight that day.	phone/online
Frontier	24 hours	phone/online	fare can be held without payment
JetBlue	Not allowed		JetBlue does not overbook flights
Southwest	24 hours	phone	only applies to reservations made by phone
United	24 hours	phone/online
US Airways	24 hours	phone	fare can be held only if purchased
Virgin America	24 hours	phone	fare must be purchased through call center (fee applies)
Online travel agency	Cancel with/by	How to cancel	Notes
Expedia	24 hours	by phone	See "Expedia Promise"
Orbitz	by 10 p.m. Central day after booking	online	Courtesy cancel
Priceline	by 11:30 p.m. Eastern day of booking	by phone	See "Exchange Guidance" policy
Travelocity	24 hours	by phone	See "Travelocity Guarantee" policy