You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: I am Sandra Davis. I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: No reservation found on your name.

USER: Ok, no issues. Thanks for your information.

ASSISTANT: Thank you for reaching us, have a nice day.