You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Myself Angela Lewis. Due to some urgent meeting, I am going to change my existing reservation. Can you please help me for this?

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Not a big deal, anyhow thank you very much for your service.

ASSISTANT: Thank you for contacting us, have a nice day.