You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Could you please help me to change my existing reservation due to postpone of my trip?

ASSISTANT: Sure, I am here to assist you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: My name is Jason Davis.

ASSISTANT: Wait a moment please, let me check with that. Jason Davis, we haven't found any reservation under your name in our database.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for choosing us.