You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Lisa Gonzalez.

ASSISTANT: What kind of help are you seeking from our end? Please let me know, so I can help you with it.

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

ASSISTANT: Lisa Gonzalez, please allow me to check with your previous booking for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry for the inconvenience but there is no active reservation found by your name.

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

ASSISTANT: Thank you for approaching our services. Have a nice day.