You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I assist you today?

USER: Owing to an emergency, I need to change my existing reservation. I am Thomas Adams.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, sorry to say that, no reservation was found with your good name.

USER: Thanks for assistance.

ASSISTANT: Thank you for opting us.