Hello.
user
Hello, how can I aid you today?
assistant
Can you help me to change my recent reservation because my trip dates are got postponed?
user
May I know your name to proceed further?
assistant
I am David Lewis.
user
 I am very sorry to inform you that there is no reservation found under your name in our database.
assistant
That's ok, thank you for checking.
user
Thank you for choosing us.
assistant