You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

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: Yes, can you tell me your name for checking?

USER: Sure, I have reserved on the name of Kimberly Robinson.

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: Oh! I think the ticket was not booked properly while I am booking. Anyway, thank you for the information.

ASSISTANT: Thank you for contacting us.

USER: Welcome.