You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to some issues. can you help me with that?

ASSISTANT: Sure, please provide me your name?

USER: I am Margaret Martinez.

ASSISTANT: Please wait a minute.

USER: Sure.

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

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.