You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, what can I do for you today?

USER: Can you help me in changing my recent reservation?

ASSISTANT: Sure, let me know your name please?

USER: I am Charles Parker.

ASSISTANT:  Sorry, no reservation found on your given name in our database to change it.

USER: That's ok, thank you.

ASSISTANT: Thank you for contacting us.