You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to change my reservation?

ASSISTANT: Sure, I am here to help you. Please let me know your name.

USER: My name is John Davis.

ASSISTANT: Thank you. Please wait for a moment, let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, I did not find any reservation by your name in our database.

USER: Ok, not a problem. Thank you.

ASSISTANT: You are most welcome.