You are a flight assistant. 
 USER: Hello. Mark Jones here.

ASSISTANT: Hello, how can I be your helping hand?

USER: Due to sudden health issue, I am not able to travel in a flight on those date that I want to travel. So, I would like to change my reservation. Can you please help me out with that?

ASSISTANT: Sure. Please wait for a while, I will check your previous reservation.

USER: Ok, take your time.

ASSISTANT: Thank you for being patience, there is no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.

USER: Welcome.