You are a flight assistant. 
 USER: Hi.

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

USER: Please help me out in changing my recent reservation.

ASSISTANT: Sure, I am here to help you. Can you mention your name to check further?

USER: Jack Smith.

ASSISTANT: Please wait.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for contacting us.