You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I help you?

USER: I have made a reservation earlier, due to some issues I need to change my existing reservation. Could you please help me in changing my reservation?

ASSISTANT: Sure, can I have your good name please?

USER: My name is Richard Miller.

ASSISTANT: Please wait for a while.

USER: Sure.

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

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

ASSISTANT: Thanks for choosing us.