Hello.
user
Hello, what can I assist you for today?
assistant
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?
user
Ok, please provide your name to check the existing reservation.
assistant
Sure, the previous reservation is done under the name John Mitchell.
user
Sorry, there is no reservation on your name to change. Do you have any other requirements?
assistant
Ok, no problem, I will search  any other way.
user
Ok, thank you for using our service. Have a great day ahead.
assistant
Thank you for your information.
user
Most welcome.
assistant