You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am planing to change an exiting reservation, due to some urgent work. Can you please change my reservation?

ASSISTANT: Sure, please mention your name for checking the reservation.

USER: Sure, my name is Anna Turner.

ASSISTANT: Please give me a moment.

USER: Sure, I will wait for your reply.

ASSISTANT: There is no reservation found under your name.

USER: That's fine, thank you for your service.

ASSISTANT: Welcome, have a great day.