You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I would like to change my existing reservation, due to postpone of my meeting.

ASSISTANT: Sure, I am here to help you out.

USER: Will you please avail me in changing? Thank you.

ASSISTANT: Can I have your name please?

USER: Raymond King.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Raymond King, we haven't found any reservation under your name in our database.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for choosing us.