You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: Due to health issue, I want to change my reservation. Can you help me?

ASSISTANT: Sure, I will help you in changing the reservation. May I know your name please?

USER: Ryan Lopez here.

ASSISTANT: Sorry, there are no reservations found.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for reaching us.