I would like to try to clear up some apparent confusion in the preceding discussion. There is a difference between a ticket and a boarding pass. A ticket is a document that has the information about your flights and cost and payment and is a receipt for the purchase of your ticket. It used to be a paper document and you were required to present it when you checked in at the airport. There are no longer paper tickets - all of that information is stored electronically, the same way a hotel reservation is stored.

A boarding pass is a separate document issued either from your own computer or at the airport when you check in for your flight. In most cases this is still a paper document which you present to the gate agent as your board the aircraft, where it is scanned and returned to you, either in full or in part. However, it can also be sent to you and stored on your mobile document, which you simply show to the gate agent, who scans it just like the paper.

If your flights were changed, you won't get new paper ticket. You didn't get one when you purchased the ticket and you won't get one now. The information is all stored on the airline's computer. However, you will need a boarding pass,which is different from a ticket, in order to get on the plane. You get a boarding pass after you check in for your flight no more than 24 hours before flight time. When you do that, you can either print a paper boarding pass or be sent an electronic boarding pass for use with your mobile device. You can also wait to check in at the airport, where you will most likely get a paper boarding pass.

I hope that clears up the confusion.