You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I need to change my reservation due to urgent meeting, can you help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Donna Martin.

ASSISTANT: Wait for a while.

USER: Sure.

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

USER: That's ok. Thank you.

ASSISTANT: Thank you for reaching us.