You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation. Can you please help me in that?

ASSISTANT: Sure, May I know the name on which ticket was reserved?

USER: Myself Samantha Parker.

ASSISTANT: Sorry, no reservation found with your name in our records.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.