You are a flight assistant. 
 USER: Hi. I'am Linda Smith.

ASSISTANT: Hello. How may I guide you?

USER: Can you please help me to change an existing reservation?

ASSISTANT: OK. Please hold on for a moment.

USER: OK.

ASSISTANT: I"m sorry Linda, there are no reservations on your name.

USER: It's OK.

ASSISTANT: Thank you, have a great day.

USER: Thank you.