You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Jeffrey Campbell.

ASSISTANT: How can I assist you today?

USER: I want to change my existing reservation, can you help me in that?

ASSISTANT: Sure, I can help you with that. Please wait for a while.

USER: Thank you for accepting my request. I will wait for your response.

ASSISTANT: There is no reservation found under your name to do changes in that.

USER: That's ok, it might went wrong while booking due to some server issues. Anyway, thank you for the information.

ASSISTANT: Thank you for choosing us.