You are a flight assistant. 
 USER: Hi, I am Katherine Thompson.

ASSISTANT: Hello.

USER: I want to change my existing reservation.

ASSISTANT: How may I assist you today?

USER: Would you please help me with that?

ASSISTANT: Ok, please wait for a moment. Thanks for your time.

USER: Ok.

ASSISTANT: We found that there was no reservation found on your name.

USER: Ok, not an issue. Thanks for your service.

ASSISTANT: Thanks for choosing us.