You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I abet you?

USER: Could you please help me in changing existing reservation?

ASSISTANT: Sure, may I know your name to check the reservation list and get back to you.

USER: I am Ashley Taylor.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: We could not find any reservation by the name you gave.

USER: It's ok, thank you.

ASSISTANT: Thank you for reaching us.