You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

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

ASSISTANT: Sure, I can help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: I am Thomas Walker.

ASSISTANT: Please wait a while I will check the reservation status.

USER: Sure.

ASSISTANT:  Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.