You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you today?

USER: I am Samuel Smith.

ASSISTANT: Ok.

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

ASSISTANT: Sure.

USER: Ok.

ASSISTANT: Thanks for your time, I did not find your name in the reservation list, to proceed further. Thank you for reaching us.

USER: Not an issue. Thank you.