You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am James Martinez.

ASSISTANT: How can I assist you?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, please wait I will revert you in a moment.

USER: Ok.

ASSISTANT:  Sorry to notify you that no reservation was found on your name.

USER: No issue. Thank you.

ASSISTANT:  Thank you for availing us.