You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I help you?

USER: I am David Allen. I want to change my reservation as my plan to meet my share holder is postponed. Can you help me with that?

ASSISTANT: Sure, I am here to help you. Please wait for a moment to check your details.

USER: Sure.

ASSISTANT: Sorry to say, no reservation found on your name.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thank you for reaching us, have a nice day.