You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Elizabeth Lopez.

ASSISTANT: How can I help you at this moment?

USER: I would like to change my existing reservation, please help m out.

ASSISTANT: Sure, I will help you with this. Please be on hold for a moment.

USER: Sure, take your time.

ASSISTANT: Elizabeth Lopez, I didn't find any active reservation under your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.