You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I am Alexander Gonzalez, can you help me to change my existing reservation?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait for a moment, while I search for the reservation on your name.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry there is no reservation found on your name in our system data.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for visiting us, have a nice day ahead.