You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I be your helping hand today?

USER: I have planned for a trip and made a reservation yesterday. But now some friends have a problem to visit the trip. So, I want to change my reservation. Can you help me with that?

ASSISTANT: Sure, I can help you. May I know your name to change your reservation?

USER: Thank you. Sure, Helen Harris is my name.

ASSISTANT: Sorry, we did not find any reservation on your name to change.

USER: Ok, Not a problem. Thanks for your kind information.

ASSISTANT: Thank you for approaching us.