How to buy flight tickets
Things You'll Need
E-ticket or reservation number
Full-fare (sometimes called "unrestricted") airline tickets in any class of service are the easiest to exchange. These tickets are mostly sold to business travelers who buy at the last minute or need lots of flexibility. When you search for these fares through United Airlines' Web site, www.ual.com, they are labeled "refundable." United Airlines will fully refund this kind of ticket if you cancel it before your flight departs, and in most cases you can make changes at no charge for any reason. If you are a member of United's Mileage Plus program, the easiest way to cancel or exchange unrestricted tickets is to go to ual.com, select the "Services and Information" menu and choose the "Refunds" option. You can also cancel or change refundable tickets by calling 1-800-864-8331. If you booked through a travel agent or a third-party site, you may need to contact the agent or site to change your ticket.
Most leisure travelers and some business travelers book nonrefundable, or restricted, airline tickets. These fares are cheaper but often carry hefty cancellation or exchange penalties. In most cases, you will not receive a refund; instead, the airline will give you a credit you can use toward a future ticket. This credit usually expires about a year from the date you exchange the ticket. In addition, United Airlines usually charges fees to passengers exchanging nonrefundable tickets; your credit will be the value of your original ticket minus the fees, which are $150 for a domestic nonrefundable ticket
and $150 to $250 for international tickets. Go to ual.com or call 1-800-864-8331 to change your ticket. United reservations agents at airport ticket counters can perform exchanges or cancellations, but this can be time-consuming and may involve extra fees. If you booked through a travel agent or a third-party site, you may need to contact the agent or site to change your ticket.
United Airlines will waive cancellation or change fees in special circumstances. If you are changing your travel plans because of a death in the family, severe illness or other emergency, call United Airlines and explain your circumstances. If you must change your ticket due to an emergency, be prepared to back up your request with documentation of your reason for the change, such as a death certificate or doctor's note. United often waives fees in advance of severe weather and encourages passengers to rebook with no penalty.
United Airlines usually will not charge you a fee if you choose standby for an earlier flight on the same day as your originally scheduled flight. However, if you want a confirmed seat, you will have to pay $75, unless you are a United 1K or Global Services elite member or are traveling on a business or first-class ticket. Call the airline at 1-800-864-8331 or speak to a reservations agent at the airport if you wish to change to a different flight on the same day. The flight must have the same routing as your original itinerary and must depart within three hours of your change request.Source: ehow.com