You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: May I know your name please?

USER: Myself Stephanie Carter.

ASSISTANT: Sure, please wait for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.