You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I want to change my reservation, can you please help me to modify my reservation?

ASSISTANT: Sure, can I know your name please?

USER: My name is Debra Clark.

ASSISTANT: Ok, wait a moment please.

USER: Sure.

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

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for approaching us.