You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I help you?

USER: I made my earlier reservation with my name Karen Nelson, Could you help me in changing my reservation?

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: Ok, thank you for quick response.

ASSISTANT: Thank you for opting us.