You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What service do you need from our agency?

USER: Due to some health issue, I want to change my existing reservation.

ASSISTANT: Sure, I am here to help you to do modifications in your past ticket. Can I know your name please?

USER: I am Jessica Phillips.

ASSISTANT: Ok, please give me sometime to check the ticket status.

USER: Ok, I will wait.

ASSISTANT: I regret to inform you, there is no reservation found under your name in our system data to change the details.

USER: Ok, Thank you.

ASSISTANT: My pleasure. Thank you for reaching us.