You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my existing reservation due to some health issues, can you help me with that?

ASSISTANT: Yes, I will help you in change of flight ticket reservation.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: My name is Jacob Thompson.

ASSISTANT: Thanks for your patience. Sorry to say that there is no flight reservation on your name change it.

USER: No problem, thank you for the checking.

ASSISTANT: Thank you.