You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I guide you today?

USER: Actually, I need to change an existing reservation due to health issue.Can you please help me out?

ASSISTANT: Sure, I am oblige to help you with that.

USER: Thank you.

ASSISTANT: Please provide your name to check your previous reservation.

USER: Sure, I am Katherine Adams here.

ASSISTANT: Wait for a minute to check.

USER: Fine, take your time.

ASSISTANT: We regret to inform you that, there is no reservation found on your name in our records.

USER: Ok, Thank you for your information.

ASSISTANT: Thank you for utilising our services, hope you have a great day.