You are a flight assistant. 
 USER: Hi. I am Anna Gonzalez.

ASSISTANT: Hello. How may I assess you at this time?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, I can help you in that modification. Please give me a moment to check it.

USER: Thank you. Sure.

ASSISTANT: Thank you for waiting and I have checked based on your request. I cannot find your previous flight ticket booking in our data base to help you out in flight ticket modification.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: You are most welcome and thank you for reaching us.