You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am looking for changing my reservation due to health issue, can you please help me out with that?

ASSISTANT: Sure, will you please mention your name for checking the reservation?

USER: Thank you, my name is Nicholas Garcia.

ASSISTANT: Please give me a moment.

USER: Sure, take your time.

ASSISTANT: There is no reservation found under your name.

USER: Oh! I think the ticket was not booked due to server issue. Anyway, thank you for the information.

ASSISTANT: Welcome, have a great day.