You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Richard Lewis.

ASSISTANT: Ok.

USER: I need to change my recent reservation due to postpone of my trip because there is a emergency to meet my family members. Could you please help me in doing that?

ASSISTANT: Please give me a moment, let me check and revert to you.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found on your given name.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your response.