You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please help me to change my reservation?

ASSISTANT: Sure, I am happy to help you. May I know your name?

USER: Sure, my name is Sandra Miller.

ASSISTANT: Sandra Miller, I did not find any reservation under your name in our database.

USER: Ok, not a problem. Thank you for informing me.

ASSISTANT: You are welcome and thank you for choosing us.