You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Richard Martinez. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, please wait for a moment. Sorry, there is no reservation found by your name.

USER: Sure. That's fine.

ASSISTANT: Thank you and have a nice day.

USER: Thank you for reaching us.