You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: I am Helen Adams.

ASSISTANT: Helen, how may I assist you?

USER: My bank exams got postponed so I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, we can help you with that. Just wait a moment, I will check our reservation list and let you know.

USER: Sure.

ASSISTANT: Helen, there is no reservation found on your name to modify.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for reaching our service.