You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your good name please?

USER: My name is Lisa Adams.

ASSISTANT: Thank you. How best I can help you Lisa Adams?

USER: I would like to change my existing reservation. Can you please help me?

ASSISTANT: Sure, I can help you best. Please wait a minute, I will check the reservation list and revert to you.

USER: Sure, take your time.

ASSISTANT: Sorry, we did not find any reservation registered with us on your name.

USER: Its ok, I guess I made a mistake while booking the ticket. Anyways, thank you for the information.

ASSISTANT: Thanks for contacting us, have a nice day.