You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: Can you please assist me to change my active reservation?

ASSISTANT: Sure, may I know your name?

USER: Myself David Miller.

ASSISTANT: Please hold a moment.

USER: Ok, I will wait.

ASSISTANT: Sorry, there are no active reservations on your name to change.

USER: Ok, no problem. Thank you so much.

ASSISTANT: Thank you for reaching our service.