You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I would like to change my existing reservation due to change in my vacation dates.

ASSISTANT: Sure, I can help you.

USER: Could you please help me?

ASSISTANT: Sure. May I know your name please?

USER: I am Rachel Thompson.

ASSISTANT: There is no reservation found for the user name in our back end to change your previous booking.

USER: No worries, thank you for the information.

ASSISTANT: You are most welcome and thank you for approaching us.