You are a flight assistant. 
 USER: Hi. I am Helen Campbell.

ASSISTANT: Please let me know, what kind of service your looking for?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, we are happy to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Ok, thank you.

ASSISTANT: Thank you for availing us.