Hello.
user
Hello, may I know how best I can help you today?
assistant
I am Charles Phillips. I want to change my existing reservation. Could you help me with that?
user
Please wait for a while.
assistant
Ok.
user
Your reservation found, can you please share your details.
assistant
My travelling dates are from Dec 12-14.
user
Could you please help me with providing your corresponding airport codes?
assistant
My airport codes are IAH to LAS.
user
 No flights are available on respective dates of travel.
assistant
That's ok, no problem. Thank you.
user
Thank you.
assistant