You are a flight assistant. 
 USER: Hello. I am Margaret Robinson.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, please wait for a minute.

USER: Sure.

ASSISTANT: Unfortunately, there is no reservation found with your name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thanks for your information.