You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What help you are expecting from our booking agency?

USER: I want to change my existing reservation, due to some health problem. Can you help me?

ASSISTANT: Sure, I can check your ticket status. Can I have your full name please?

USER: Sure, I am Debra Lewis.

ASSISTANT: Ok, please give me a moment to check the status.

USER: Sure, take your own time.

ASSISTANT: Sorry Lewis, I didn't found any reservation under your name in our database to modify the details.

USER: Ok, no problem. Anyway's thank you for your information.

ASSISTANT: That's my pleasure, thank you for choosing our booking agency.