You are a flight assistant. 
 USER: Hi. I am Kevin Parker.

ASSISTANT: Hello, how may I assist you today?

USER: Due to my health problem I want to change my existing reservation, can you please help me to change my reservation?

ASSISTANT: Sure, wait a minute.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.