You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, good evening.

USER: My self Helen Parker.

ASSISTANT: Helen, what kind of help you are looking for?

USER: Due to some problems, I want to change my existing reservation. Can you help me?

ASSISTANT: I can help you with that, can you tell me your name for changing reservation? Sorry, there is no reservation on your name.

USER: It's ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your information.

ASSISTANT: Welcome.