You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, may I know your name?

USER: Thank you for your response, I am Mary Lopez.

ASSISTANT: Please give me a moment to check your ticket status.

USER: Sure.

ASSISTANT: Sorry Mary Lopez, no reservation is available by your name.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us.