You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Is there any help that you need from my side?

USER: I am Timothy Robinson. I am planning to change an existing reservation, due to health issue. Can you please change my ticket?

ASSISTANT: Sure, I am glad to help you in ticket modification process. Please give me a moment to check it.

USER: Sure, I will wait for your reply.

ASSISTANT: Thank you for waiting, there is no reservation found for the user name in our data base to modify your flight ticket booking.

USER: That's fine. Thank you for your service.

ASSISTANT: You are most welcome and thank you for reaching our agency.