You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today to making you happy?

USER: Due to some work, I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, please let me know your good name ?

USER: Catherine Anderson here.

ASSISTANT: Sorry, no reservation matches with the given name.

USER: No problem, Thank you.

ASSISTANT: Thank you for opting us.