You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Emma Thomas.

ASSISTANT: How can I help you?

USER: As I changed my plans, can you please help me in changing my existing reservation?

ASSISTANT: Ok, please wait.

USER: Take your time.

ASSISTANT: Sorry, no reservation under your name.

USER: No problem. Thank you.

ASSISTANT: Thank you, have a nice day.