You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you now?

USER: I want to change my existing reservation due to some health issues, can you please help me in this?

ASSISTANT: Sure, I will help you with that. May I know your name please?

USER: Thank you. Sure, my name is Rebecca Wright.

ASSISTANT: Sorry Rebecca, there are no flights found on your requested dates.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us, have a nice day.

USER: Thank you for your service.