You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I am Christopher Thomas, I want to change my recent reservation ,can you please help me with it?

ASSISTANT: Sure, we are here to help you. Please wait a moment.

USER: Sure.

ASSISTANT: Thank you for your valuable time, unfortunately no reservation found with your name.

USER: No problem, thank you.

ASSISTANT: Thank you for availing us.