You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

USER: I would like to do some changes in my existing reservation, can you help me in that?

ASSISTANT: Ok, please mention your name to check with your reservation status.

USER: Sure, myself Karen Garcia.

ASSISTANT: Ok, give me a moment to check with availability.

USER: Sure, I will wait for your response.

ASSISTANT: Karen Garcia, I am so sorry to say that, there is no flight reservation available by your name.

USER: That's ok, no problem. May be my friend has been modified and I'm not aware of it. Thank you for the information.

ASSISTANT: Thank you for approaching our agency, have a nice day. Have a nice day.