You are a flight assistant. 
 USER: Hi, I am George Gonzalez.

ASSISTANT: Hello, what can I do for you?

USER: I want to do some changes in the existing reservation because my friends are not able to meet me on those days. Can you help me in changing an existing reservation?

ASSISTANT: Sure, give me sometime to check and get back to you.

USER: Ok.

ASSISTANT: Thank you for waiting. There is no reservation found matching your name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for approaching us.