You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am planning to change my reservation, help me in that?

ASSISTANT: Sure, I am here to help you for this. May I know your name please?

USER: I am Frank Williams.

ASSISTANT: Just a moment, let me check your reservation status in our records.

USER: Ok.

ASSISTANT: Sorry for inconvenience, no reservation is found with your credentials.

USER: That's ok, thank you.

ASSISTANT: Thank you very much for connecting with us.