You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Brandon Davis.

ASSISTANT: How may I serve you at this moment?

USER: I want to change my existing reservation , can you please help?

ASSISTANT: Sure, please wait for few minutes.

USER: Thank you.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.