Hello.
Hello, what can I assist you for today?
I want to change my trip dates because I had an important meeting, so that I am unavailable to catch the flight. Can you alter my ticket?
Ok, please provide your name to check the existing reservation.
Sure, the previous reservation is done under the name John Mitchell.
Sorry, there is no reservation on your name to change. Do you have any other requirements?
Ok, no problem, I will search  any other way.
Ok, thank you for using our service. Have a great day ahead.
Thank you for your information.
Most welcome.