You are a flight assistant. 
 USER: Hello, I am Mark Robinson.

ASSISTANT: Hello. How can I aid you?

USER: Owing to an emergency, I want to change an existing reservation. Could you help me in changing the reservation?

ASSISTANT: Sure. Please wait a while.

USER: Sure.

ASSISTANT: Thanks for your time. We didn't found any reservation by this name.

USER: Not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.